ClipArt ETC
Right triangle inscribed in semicircle. Illustration shows that the perpendicular from any point in the circumference to the diameter of a circle is the mean proportional between the segments of the diameter.

Right Triangle Inscribed in Semicircle Shows Mean Proportional

Right triangle inscribed in semicircle. Illustration shows that the perpendicular from any point in…

A flashcard featuring an illustration of a Point

Flashcard of a Point

A flashcard featuring an illustration of a Point

Diagram showing the circulation of blood in the heart. Let <em>a</em> represent the right side of the heart, <em>c</em>the left side, <em>b</em> the lungs, and <em>d</em> the general system of the body. The arrows point in the direction in which the blood flows. In all the shaded part the blood is dark (oxygen-poor), and in the part that is not shaded it is red (oxygen-rich).

Blood Circulation in the Heart

Diagram showing the circulation of blood in the heart. Let a represent the right side of the…

If a straight line is perpendicular to each of two other straight lines in a plane at their point of intersection, it is perpendicular to the plane of the two lines.

Line Perpendicular to Plane

If a straight line is perpendicular to each of two other straight lines in a plane at their point of…

Straight line AB is perpendicular to the lines in plane MN at point B.

Line Perpendicular to Plane

Straight line AB is perpendicular to the lines in plane MN at point B.

Oblique lines drawn from a point to a plane.

Oblique Lines Drawn to a Plane

Oblique lines drawn from a point to a plane.

"The locus of a point in space equidistant from the extremities of a straight line is the plane perpendicular to this line at its middle point."

Locus Point to a Plane

"The locus of a point in space equidistant from the extremities of a straight line is the plane perpendicular…

Straight line AB is perpendicular to the lines in plane MN at point B. "If from the foot of a perpendicular to a plane a straight line is drawn at right angles to any line in the plane, the line drawn from its intersection with the line in the plane to any point of the perpendicular is perpendicular to the line of the plane."

Line Perpendicular to Plane

Straight line AB is perpendicular to the lines in plane MN at point B. "If from the foot of a perpendicular…

Illustration of a dihedral angle bisected by a plane. "Every point in a plane which bisects a dihedral angle is equidistant from the faces of the angle."

Dihedral Angle With Bisector

Illustration of a dihedral angle bisected by a plane. "Every point in a plane which bisects a dihedral…

Illustration of polyhedral angle. "The opening of three or more planes which meet at a common point is called a polyhedral angle."

Polyhedral Angle

Illustration of polyhedral angle. "The opening of three or more planes which meet at a common point…

A sphere with quadrants and poles. "A point on the surface of a sphere, which is at the distance of a quadrant from each of two other points, not the extremities of a diameter, is a pole of the great circle passing through theses points."

Sphere With Quadrants and Poles

A sphere with quadrants and poles. "A point on the surface of a sphere, which is at the distance of…

Illustration of a parabola - a curve which is the locus of a point that moves in a plane so that its distance from a fixed point in the plane is always equal to its distance from a fixed line in the plane.

Parabola With Focus and Directrix

Illustration of a parabola - a curve which is the locus of a point that moves in a plane so that its…

Illustration of a parabola - a curve which is the locus of a point that moves in a plane so that its distance from a fixed point (focus) in the plane is always equal to its distance from a fixed line (directrix) in the plane.

Parabola With Focus and Directrix

Illustration of a parabola - a curve which is the locus of a point that moves in a plane so that its…

Illustration of a parabola showing that any point of a parabola is the mean proportional between the latus rectum (focal chord) and the abscissa (x-coordinate).

Parabola With Coordinates and Latus Rectum

Illustration of a parabola showing that any point of a parabola is the mean proportional between the…

Illustration of a parabola showing point P is equidistant to the focus and the directrix.

Point on Parabola

Illustration of a parabola showing point P is equidistant to the focus and the directrix.

Illustration of a parabola. "If a line PT is drawn from any point P of the curve, bisecting the angle between PF and the perpendicular from P to the directrix, every point of the line PT, except P, is without the curve."

Point on Parabola

Illustration of a parabola. "If a line PT is drawn from any point P of the curve, bisecting the angle…

"When a person speaks into the transmitter, the pulsations of the air, produced by the voice, produce the slight vibrations of the diaphragm...and these vary the pressure of the platinum point on the carbon disk, and these vary the strength of the electric current, and reproduce precisely similar vibrations in the diaphragm of the receiver, at the opposite end of the line, which reproduce the spoken words." -Atkinson 1903

Electric Telephone

"When a person speaks into the transmitter, the pulsations of the air, produced by the voice, produce…

Illustration of a tangent line drawn from an external point to a parabola.

Tangent to a Parabola

Illustration of a tangent line drawn from an external point to a parabola.

Illustration showing that if two tangents RP and RQ are drawn from a point R to a parabola, the line drawn through R parallel to the axis bisects the chord of contact.

Tangents to a Parabola

Illustration showing that if two tangents RP and RQ are drawn from a point R to a parabola, the line…

Illustration showing the definition of an ellipse. "An ellipse is a curve which is the locus of a point that moves in a plane so that the sum of its distances from two fixed points in the plane is constant." The foci and major axis is drawn.

Demonstration of Ellipse Definition

Illustration showing the definition of an ellipse. "An ellipse is a curve which is the locus of a point…

Illustration of half of an ellipse. "If d denotes the abscissa of a point of an ellipse, r and r' its focal radii, then r'=a+ed, r=a-ed."

Focal Radii of an Ellipse

Illustration of half of an ellipse. "If d denotes the abscissa of a point of an ellipse, r and r' its…

Illustration of half of an ellipse. The square of the ordinate of a point in an ellipse is to the product of the segments of the major axis made by the ordinate as the square of b to the square of a.

Ordinate and Major Axis of Ellipse

Illustration of half of an ellipse. The square of the ordinate of a point in an ellipse is to the product…

Illustration of half of an ellipse. "The sum of the distances of any point from the foci of an ellipse is greater than or less than 2a, according as the point is without or within the curve."

Point Distances to Foci on Ellipse

Illustration of half of an ellipse. "The sum of the distances of any point from the foci of an ellipse…

Illustration of half of an ellipse. "If through a point P of an ellipse a line is drawn bisecting the angle between one of the focal radii and the other produced, every point in this line except P is without the curve."

Line Bisecting Angle Between Focal Radii on Ellipse

Illustration of half of an ellipse. "If through a point P of an ellipse a line is drawn bisecting the…

Illustration of how to draw a tangent to an ellipse from an external point.

Tangent From External Point to an Ellipse

Illustration of how to draw a tangent to an ellipse from an external point.

Illustration showing the tangents drawn at two corresponding points of an ellipse and its auxiliary circle cut the major axis produced at the same point.

Tangents to an Ellipse

Illustration showing the tangents drawn at two corresponding points of an ellipse and its auxiliary…

Illustration showing that tangents drawn at the ends of any diameter are parallel to each other.

Parallel Tangents to an Ellipse

Illustration showing that tangents drawn at the ends of any diameter are parallel to each other.

Illustration showing the definition of an hyperbola. "An hyperbola may be described by the continuous motion of a point, as follows: To one of the foci F' fasten one end of a rigid bar F'B so that it is capable of turning freely about F' as a center in the plane of the paper."

Demonstration of Hyperbola Definition

Illustration showing the definition of an hyperbola. "An hyperbola may be described by the continuous…

Illustration of a point on a hyperbola. "If d denotes the abscissa (x-coordinate) of a point of an hyperbola, r and r' its focal radii, then r = ed - a, and r' = ed + a."

Point on a Hyperbola

Illustration of a point on a hyperbola. "If d denotes the abscissa (x-coordinate) of a point of an hyperbola,…

Illustration of a hyperbola and its auxiliary circle. "Any ordinate of a hyperbola is to the tangent from its foot to the auxiliary circle as b is to a."

Auxiliary Circle and Hyperbola

Illustration of a hyperbola and its auxiliary circle. "Any ordinate of a hyperbola is to the tangent…

Illustration of a hyperbola with distances to foci drawn. "The difference of the distances of any point from the foci of an hyperbola is greater than or less than 2a, according as the point is on the concave or convex side of the curve."

Foci Distance of Hyperbola

Illustration of a hyperbola with distances to foci drawn. "The difference of the distances of any point…

Illustration of a hyperbola with a line bisecting the focal radii. "If through a point P of an hyperbola a line is drawn bisecting the angle between the focal radii, every point in this line except P is on the convex side of the curve.

Line Bisecting Angle Between Focal Radii in Hyperbola

Illustration of a hyperbola with a line bisecting the focal radii. "If through a point P of an hyperbola…

Illustration showing how to draw a tangent to an hyperbola from a given point P on the convex side of the hyperbola.

Tangent to Hyperbola

Illustration showing how to draw a tangent to an hyperbola from a given point P on the convex side of…

Illustration of intersecting lines with A being the point of intersection.

Intersecting Lines

Illustration of intersecting lines with A being the point of intersection.

Illustration of tangent circles. One circle is said to be tangent to another circle when they touch each other at one point only.

Tangent Circles

Illustration of tangent circles. One circle is said to be tangent to another circle when they touch…

"If from any point on the circumference of a circle, a perpendicular be let fall upon a given diameter, this perpendicular will be a mean proportional between the two parts into which it divides the diameter."

Circle With a Perpendicular Drawn to the Diameter

"If from any point on the circumference of a circle, a perpendicular be let fall upon a given diameter,…

Illustration of an ellipse with major and minor axes, foci, and points on the ellipse. "An ellipse is a plane figure bounded by a curved line, to any point of which the sum of the distances from two fixed points within, called the foci, is equal to the sum of the distances from the foci to any other point on the curve."

Ellipse

Illustration of an ellipse with major and minor axes, foci, and points on the ellipse. "An ellipse is…

Trime (3 cents) United States coin from 1851. Obverse has the Union shield lying on top of a six-pointed star and is inscribed with - UNITED STATES OF AMERICA with the date at the bottom. Reverse shows by a large, scrolled letter C enclosing the Roman numeral III (denoting value). This image is surrounded 13 equally-spaced stars.

Silver Trime Coin, 1851

Trime (3 cents) United States coin from 1851. Obverse has the Union shield lying on top of a six-pointed…

A 5-point star made from a non-regular concave decagon in which all sides are equal in length.

Concave Equilateral Decagon

A 5-point star made from a non-regular concave decagon in which all sides are equal in length.

A 6-point star made from a non-regular concave dodecagon in which all sides are equal in length. There is vertical, horizontal, rotational, and diagonal symmetry.

Concave Equilateral Dodecagon

A 6-point star made from a non-regular concave dodecagon in which all sides are equal in length. There…

Circular rosette with 6 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles are less than the distance between the point of rotation and the center of the circle. Thus, there is a hole in the center.

Circular Rosette With 6 Petals

Circular rosette with 6 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 12 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles are less than the distance between the point of rotation and the center of the circle. Thus, there is a hole in the center.

Circular Rosette With 12 Petals

Circular rosette with 12 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 24 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles are less than the distance between the point of rotation and the center of the circle. Thus, there is a hole in the center.

Circular Rosette With 24 Petals

Circular rosette with 24 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 48 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles are less than the distance between the point of rotation and the center of the circle. Thus, there is a hole in the center.

Circular Rosette With 48 Petals

Circular rosette with 48 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 6 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles is equal to the distance between the point of rotation and the center of the circle. Thus, the circles meet in the center of the larger circle.

Circular Rosette With 4 Petals

Circular rosette with 6 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular design made by rotating circles about a fixed point. The radii of the smaller circles is equal to the distance between the point of rotation and the center of the circle. The circles meet in the center of the larger circle. The design is achieved by removing consecutive halves of the circles (semi-circles).

Circular Design

Circular design made by rotating circles about a fixed point. The radii of the smaller circles is equal…

Circular design made by rotating circles about a fixed point. The radii of the smaller circles is equal to the distance between the point of rotation and the center of the circle. The circles meet in the center of the larger circle. The design is achieved by removing consecutive halves of the circles (semi-circles).

Circular Design

Circular design made by rotating circles about a fixed point. The radii of the smaller circles is equal…

Circular rosette with 8 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles is equal to the distance between the point of rotation and the center of the circle. Thus, the circles meet in the center of the larger circle.

Circular Rosette With 8 Petals

Circular rosette with 8 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 16 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles is equal to the distance between the point of rotation and the center of the circle. Thus, the circles meet in the center of the larger circle.

Circular Rosette With 16 Petals

Circular rosette with 16 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 32 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles is equal to the distance between the point of rotation and the center of the circle. Thus, the circles meet in the center of the larger circle.

Circular Rosette With 32 Petals

Circular rosette with 32 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 8 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles are less than the distance between the point of rotation and the center of the circle. Thus, there is a hole in the center.

Circular Rosette With 8 Petals

Circular rosette with 8 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 16 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles are less than the distance between the point of rotation and the center of the circle. Thus, there is a hole in the center.

Circular Rosette With 16 Petals

Circular rosette with 16 petals in a circle. It is made by rotating circles about a fixed point. The…

Circular rosette with 32 petals in a circle. It is made by rotating circles about a fixed point. The radii of the smaller circles are less than the distance between the point of rotation and the center of the circle. Thus, there is a hole in the center.

Circular Rosette With 32 Petals

Circular rosette with 32 petals in a circle. It is made by rotating circles about a fixed point. The…

A sequence of five circles tangent to each other at a point. The radius decreases by one half in each successive circle.

5 Tangent Circles

A sequence of five circles tangent to each other at a point. The radius decreases by one half in each…

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward the center of the circle. (The arcs are inverted.) The design is then repeated and rotated 45&deg; to create the star-like illustration in scribed in the circle.

Reflected Arcs Of 2 Circles In A Circle

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward…

A design created by dividing a circle into 4 equal arcs and reflecting each arc toward the center of the circle. (The arcs are inverted.) The design is then repeated and rotated 45&deg; to create the star-like illustration.

Reflected Arcs Of 2 Circles

A design created by dividing a circle into 4 equal arcs and reflecting each arc toward the center of…

A design created by dividing a circle into 4 equal arcs and reflecting each arc toward the center of the circle. (The arcs are inverted.) The design is then repeated and rotated 45&deg; and the overlapping curves are removed to create the star-like illustration.

Reflected Arcs Of 2 Circles

A design created by dividing a circle into 4 equal arcs and reflecting each arc toward the center of…

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward the center of the circle. (The arcs are inverted.) The design is then repeated (a total of four times) and rotated 22.5&deg; to create the star-like illustration in scribed in the circle.

Reflected Arcs Of 4 Circles In A Circle

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward…

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward the center of the circle. (The arcs are inverted.) The design is then repeated (a total of four times) and rotated 22.5&deg; to create the star-like illustration.

Reflected Arcs Of 4 Circles In A Circle

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward…

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward the center of the circle. (The arcs are inverted.) The design is then repeated (a total of eight times) and rotated 11.25&deg; to create the star-like illustration in scribed in the circle.

Reflected Arcs Of 8 Circles In A Circle

A design created by dividing a circle into 4 equal arcs and creating a reflection of each arc toward…