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OP is a line representing a vector (directed quantity)

Vector

OP is a line representing a vector (directed quantity)

OP is a vector (directed quantity) showing the force by a weight acting on it at an angle of 20 degrees.

Vector Showing Force at Angle of 20 degrees

OP is a vector (directed quantity) showing the force by a weight acting on it at an angle of 20 degrees.

Illustration showing an angle of elevation from a horizontal line to a line of sight.

Angle of Elevation

Illustration showing an angle of elevation from a horizontal line to a line of sight.

Illustration showing an angle of depression from a horizontal line to a line of sight.

Angle of Depression

Illustration showing an angle of depression from a horizontal line to a line of sight.

Illustration showing an angle of 23 degrees 40 minutes making a triangle in a city block and marking off streets at 100 foot intervals.

Triangular City Block With Angles and Lengths

Illustration showing an angle of 23 degrees 40 minutes making a triangle in a city block and marking…

Illustration showing a survey on the lake front in Chicago with distances and angle measures shown.

Survey of Lake Front in Chicago

Illustration showing a survey on the lake front in Chicago with distances and angle measures shown.

Illustration showing a circle inscribed in a regular pentagon. Or, a regular pentagon circumscribed about a circle.

Regular Pentagon With Circle Inscribed

Illustration showing a circle inscribed in a regular pentagon. Or, a regular pentagon circumscribed…

Roof with a slope of 30 degrees. Angle theta is the inclination to the horizontal of the line AB, drawn in the roof and making an angle of 35 degrees with the line of greatest slope.

Roof With 30 degree Inclination for Trigonometry Triangle Problems

Roof with a slope of 30 degrees. Angle theta is the inclination to the horizontal of the line AB, drawn…

Spiral with lines AB and CD drawn on piece of paper shown flat.

Spiral Drawn on Piece of Paper Shown Flat

Spiral with lines AB and CD drawn on piece of paper shown flat.

Spiral with lines AB and CD drawn on piece of paper and rolled into a cylinder to form spiral running from A to D.

Spiral Drawn on Piece of Paper and Rolled

Spiral with lines AB and CD drawn on piece of paper and rolled into a cylinder to form spiral running…

Angle XOP=Θ and angle XOQ=90+Θ. From a point in the terminal side of each a perpendicular line is drawn to the x-axis. The right triangles AOB and OCD thus formed are similar, and have all their sides positive except OC

Coordinate Axis With Perpendiculars Drawn To Form Similar Right Triangles

Angle XOP=Θ and angle XOQ=90+Θ. From a point in the terminal side of each a perpendicular line is…

Angle XOP=Θ and angle XOQ=- Θ. From a point in the terminal side of each a perpendicular line is drawn to the x-axis. The right triangles OAB and OAC thus formed are similar, and have all their sides positive except AC, which is negative.

Coordinate Axis With Perpendiculars Drawn To Form Similar Right Triangles From Positive and Negative Theta, Θ

Angle XOP=Θ and angle XOQ=- Θ. From a point in the terminal side of each a perpendicular line is drawn…

Diagrams of spinal cord and nerve roots. Labels: A, a small portion of the cord seen from the ventral side; B, the same seen laterally; C, a cross-section of the cord; D, the two roots of a spinal nerve; 1, anterior (ventral) fissure; 2, posterior (dorsal) fissure; 3, surface groove along the line of attachment of the anterior nerve roots; 4, line of origin of the posterior roots; 5, anterior root filaments of a spinal nerve; 6, posterior root filaments; 6', ganglion of the posterior root; 7, 7', the first two divisions of the nerve trunk after its formation by the union of the two roots.

Spinal Cord and Nerve Roots

Diagrams of spinal cord and nerve roots. Labels: A, a small portion of the cord seen from the ventral…

To illustrate the structure of nerve fibers. Labels: A, nerve fiber examined fresh; n, node. B, nerve fiber with axis cylinder shaded, and medulla represented by dark lines; n.c, nucleus; p, granular cell substance near the nucleus. C, more highly magnified: m, medulla; n, node. D, nerve treated with reagents to show the axis cylinder: n.x, surrounded by medulla, m. E, nerve treated with reagents to show n.c, nucleus with fine line over it representing the neurilemma, and outside this fine connective tissue, c: n.c', nucleus lying in the fine connective tissue. F, nerve fiber deprived of its neurilemma showing medulla broken up into fragments, m, surrounding the axis cylinder, n.x.

Nerve Fibers

To illustrate the structure of nerve fibers. Labels: A, nerve fiber examined fresh; n, node. B, nerve…

The left eyeball in horizontal section from before back. Labels: 1, sclerotic; 2, junction of sclerotic and cornea; 3, cornea; 4,5, conjunctiva; 6, posterior elastic layer of cornea; 7, ciliary muscle; 10, choroid; 11,13, ciliary processes; 14, iris; 15, retina; 16, optic nerve; 17, artery entering retina in optic nerve; 18, fovea centralis; 19, region where sensory part of retina ends; 22, suspensory ligament; 23 is placed in the canal of Petit, and the line from 25 points to it; 24, the anterior part of the hyaloid membrane; 26, 27, 28, are placed on the lends; 28 points to the line of attachment around it of the suspensory ligament; 29, vitreous humor; 30, anterior chamber of aqueous humor; 31, posterior chamber of aqueous humor.

Section of Left Eyeball

The left eyeball in horizontal section from before back. Labels: 1, sclerotic; 2, junction of sclerotic…

A vertical section of the head and neck through the mesial line, in order to show the opening of the Eustachian tube and its relation to the pharynx.

A Vertical Section of the Head and Neck

A vertical section of the head and neck through the mesial line, in order to show the opening of the…

An illustration of a straight line/segment.

Straight Line

An illustration of a straight line/segment.

An illustration of a curved line.

Curved Line

An illustration of a curved line.

An illustration of a broken line.

Broken Line

An illustration of a broken line.

An illustration of a straight line with a point.

Straight Line With Point

An illustration of a straight line with a point.

An illustration of a straight line with 5 points dividing it into 4 equal parts. Multiple of a given line.

Straight Line With Points Divided Into Equal Parts

An illustration of a straight line with 5 points dividing it into 4 equal parts. Multiple of a given…

An illustration of angles with the same vertex made up of 4 lines.

Angles With Same Vertex

An illustration of angles with the same vertex made up of 4 lines.

An illustration showing when one straight line meets another straight line and makes the adjacent angles equal, each of these angles is called a right angle.

Right Angles With Same Vertex

An illustration showing when one straight line meets another straight line and makes the adjacent angles…

An illustration of two angles that are adjacent. They have the same vertex and a common side between them. Angles BOD and AOD are adjacent

Adjacent Angles

An illustration of two angles that are adjacent. They have the same vertex and a common side between…

An illustration showing a straight angle. When the sides of an angle extend in opposite directions, so as to be in the same straight line, the angle is called a straight angle.

Straight Angle

An illustration showing a straight angle. When the sides of an angle extend in opposite directions,…

Vertical angles are when two angles have the same vertex, and the sides of the one are prolongations of the sides of the other. In this illustration, a and b are vertical angles and c and d are vertical angles.

Vertical Angles

Vertical angles are when two angles have the same vertex, and the sides of the one are prolongations…

Illustration of supplementary angles. Two angles whose sum is a straight angle.

Supplementary Angles

Illustration of supplementary angles. Two angles whose sum is a straight angle.

Illustration of supplementary angles. Two angles whose sum is a straight angle. This can be used tow show the Theorem: If two adjacent angles have their exterior sides in a straight line, these angles are supplementary.

Supplementary Angles

Illustration of supplementary angles. Two angles whose sum is a straight angle. This can be used tow…

Illustration of supplementary angles. Two angles whose sum is a straight angle. This can be used tow show the Theorem: If two adjacent angles are supplementary, their exterior sides are in the same straight line.

Supplementary Angles

Illustration of supplementary angles. Two angles whose sum is a straight angle. This can be used tow…

Illustration of two lines intersecting at a point. This can be used to show vertical angles.

Intersecting Straight Lines

Illustration of two lines intersecting at a point. This can be used to show vertical angles.

Illustration of two straight lines drawn from a point in a perpendicular to a given line, cutting off on the given line equal segments from the foot of the perpendicular, are equal and make equal angles with the perpendicular. This illustration can be used to show the proof.

Lines Drawn to Another Line to Form Triangle

Illustration of two straight lines drawn from a point in a perpendicular to a given line, cutting off…

Illustration showing only one perpendicular can be drawn to a given line from a given external point.

Perpendicular Line Drawn to a Given Line from an External Point

Illustration showing only one perpendicular can be drawn to a given line from a given external point.

Illustration showing that the perpendicular is the shortest line that can be drawn to a straight line from an external point.

Perpendicular Line Drawn To a Given Line From an External Point

Illustration showing that the perpendicular is the shortest line that can be drawn to a straight line…

Illustration showing two lines CA and CB drawn from the point C to the extremities of the straight line AB. OA and OB are two lines similarly drawn, but included by CA and CB. This can be used to show the theorem: The sum of two lines drawn from a point to the extremities of a straight line is greater than the sum of two other lines similarly drawn, but included by them.

Lines Drawn From the Point C to the Extremities of the Straight line AB

Illustration showing two lines CA and CB drawn from the point C to the extremities of the straight line…

Illustration showing two straight lines drawn from the same point in a perpendicular to a given line, cutting off on the line unequal segments from the foot of the perpendicular, the more remote is the greater.

Lines Drawn From the Same Point in a Perpendicular to a Given line, Cutting Off Segments

Illustration showing two straight lines drawn from the same point in a perpendicular to a given line,…

Illustration showing two straight lines in the same plane perpendicular to the same straight line are parallel.

Parallel Lines

Illustration showing two straight lines in the same plane perpendicular to the same straight line are…

Illustration showing if a straight line is perpendicular to one of two parallel lines, it is perpendicular to the other also.

Parallel Lines

Illustration showing if a straight line is perpendicular to one of two parallel lines, it is perpendicular…

Illustration showing that a transversal is a straight line that cuts two or more straight lines.

Lines Cut By A Transversal

Illustration showing that a transversal is a straight line that cuts two or more straight lines.

Illustration showing that if two parallel lines are cut by a transversal, then the alternate interior angles are equal.

Parallel Lines Cut By A Transversal

Illustration showing that if two parallel lines are cut by a transversal, then the alternate interior…

Illustration showing that when two straight lines in the same plane are cut by a transversal, if the alternate interior angles are equal, the two straight lines are parallel.

Parallel Lines Cut By A Transversal

Illustration showing that when two straight lines in the same plane are cut by a transversal, if the…

Illustration showing that when two parallel lines are cut by a transversal, the exterior-interior angles are equal.

Parallel Lines Cut By A Transversal

Illustration showing that when two parallel lines are cut by a transversal, the exterior-interior angles…

Illustration showing that when two parallel lines are cut by a transversal, the two interior angles on the same side of the transversal are supplementary.

Parallel Lines Cut By A Transversal

Illustration showing that when two parallel lines are cut by a transversal, the two interior angles…

Illustration showing a triangle with an interior segment drawn

Triangle With Interior Segment

Illustration showing a triangle with an interior segment drawn

Illustration showing a triangle with an exterior segment drawn to show and exterior angle. This can be shown to show adjacent angles ACB and ACD as well.

Triangle With Segment Extended for Exterior Angle

Illustration showing a triangle with an exterior segment drawn to show and exterior angle. This can…

Illustration showing an isosceles triangle with a segment inside. This can be used to show that in an isosceles triangle the angles opposite the equal sides are equal.

Isosceles Triangle With Interior Segment Drawn

Illustration showing an isosceles triangle with a segment inside. This can be used to show that in an…

Illustration showing a triangle with a segment inside.

Triangle With Interior Segment Drawn

Illustration showing a triangle with a segment inside.

Illustration showing that the perpendicular bisector of a given line is the locus of points equidistant from the extremities of the line.

Perpendicular Bisector of a Line

Illustration showing that the perpendicular bisector of a given line is the locus of points equidistant…

Illustration showing that the bisector of a given angle is the locus of points equidistant from the sides of the angle.

Angle Bisector

Illustration showing that the bisector of a given angle is the locus of points equidistant from the…

Illustration of two parallel lines with equal segments between them. Two parallel lines are everywhere equally distant.

Parallel Lines With Equal Segments Between

Illustration of two parallel lines with equal segments between them. Two parallel lines are everywhere…

Illustration showing that when three or more parallel lines intercept equal parts on one transversal, they intercept equal parts on every transversal.

Parallel Lines Cut By A Transversal

Illustration showing that when three or more parallel lines intercept equal parts on one transversal,…

Illustration of a triangle showing that when a line parallel to the base of a triangle bisects one side, it bisects the other side also.

Triangle With Bisector Parallel to the Base

Illustration of a triangle showing that when a line parallel to the base of a triangle bisects one side,…

Illustration of a polygon with a diagonal drawn. A diagonal of a polygon is a line joining the vertices of two angles not adjacent (AC).

Polygon With Diagonal

Illustration of a polygon with a diagonal drawn. A diagonal of a polygon is a line joining the vertices…

Illustration of an axis of symmetry drawn with respect to a straight line.

Axis of Symmetry

Illustration of an axis of symmetry drawn with respect to a straight line.

Illustration of an axis of symmetry drawn with respect to a hexagon.

Axis of Symmetry Drawn on a Hexagon

Illustration of an axis of symmetry drawn with respect to a hexagon.

Illustration of an axis of symmetry drawn with respect to a hexagon.

Axis of Symmetry Drawn on a Hexagon

Illustration of an axis of symmetry drawn with respect to a hexagon.

Illustration of an axis of symmetry drawn with respect to a quadrilateral.

Axis of Symmetry Drawn on a Quadrilateral

Illustration of an axis of symmetry drawn with respect to a quadrilateral.

Illustration of a quadrilateral which has two adjacent sides equal and the other two sides equal. It is symmetrical with respect to the diagonal joining the vertices of the angles formed by the equal sides, and the diagonals are perpendicular to each other.

Quadrilateral with Symmetry

Illustration of a quadrilateral which has two adjacent sides equal and the other two sides equal. It…

Illustration of a triangle with a segment parallel to the base.

Triangle With Parallel Segment Drawn

Illustration of a triangle with a segment parallel to the base.

Illustration to show that if an angle is bisected, and if a line drawn through the vertex perpendicular to the bisector, this line forms equal angles with the sides of the given angle.

Bisected Angle

Illustration to show that if an angle is bisected, and if a line drawn through the vertex perpendicular…

Illustration to show that if one of the legs of an isosceles triangle is produced through the vertex by its own length, the line joining he end of the leg produced to the nearer end of the base is perpendicular to the base.

Leg Produced through the Vertex of an Isosceles Triangle

Illustration to show that if one of the legs of an isosceles triangle is produced through the vertex…