ClipArt ETC
Illustration of a regular hexagon inscribed in a circle. This can also be described as a circle circumscribed about a regular hexagon. All diagonals of the hexagon are also diameters of the circle. The diagonals intersect at the center of both the hexagon and the circle.

Regular Hexagon Inscribed In A Circle

Illustration of a regular hexagon inscribed in a circle. This can also be described as a circle circumscribed…

Illustration of a regular hexagon circumscribed about a circle. This can also be described as a circle inscribed in a regular hexagon.

Regular Hexagon Circumscribed About A Circle

Illustration of a regular hexagon circumscribed about a circle. This can also be described as a circle…

Illustration of a regular heptagon/septagon inscribed in a circle. This can also be described as a circle circumscribed about a regular heptagon/septagon.

Regular Heptagon/Septagon Inscribed In A Circle

Illustration of a regular heptagon/septagon inscribed in a circle. This can also be described as a circle…

Illustration of a regular heptagon/septagon circumscribed about a circle. This can also be described as a circle inscribed in a regular heptagon/septagon.

Regular Heptagon/Septagon Circumscribed about a Circle

Illustration of a regular heptagon/septagon circumscribed about a circle. This can also be described…

Illustration of a regular octagon inscribed in a circle. This can also be described as a circle circumscribed about a regular octagon.

Regular Octagon Inscribed In A Circle

Illustration of a regular octagon inscribed in a circle. This can also be described as a circle circumscribed…

Illustration of a regular octagon circumscribed about a circle. This can also be described as a circle inscribed in a regular octagon.

Regular Octagon Circumscribed About A Circle

Illustration of a regular octagon circumscribed about a circle. This can also be described as a circle…

Illustration of a regular nonagon inscribed in a circle. This can also be described as a circle circumscribed about a regular nonagon.

Regular Nonagon Inscribed In A Circle

Illustration of a regular nonagon inscribed in a circle. This can also be described as a circle circumscribed…

Illustration of a regular nonagon circumscribed about a circle. This can also be described as a circle inscribed in a regular nonagon.

Regular Nonagon Circumscribed About A Circle

Illustration of a regular nonagon circumscribed about a circle. This can also be described as a circle…

Illustration of a cyclic pentagon, a pentagon inscribed in a circle. This can also be described as a circle circumscribed about a pentagon. In this illustration, the pentagon is not regular (the lengths of the sides are not equal).

Cyclic Pentagon

Illustration of a cyclic pentagon, a pentagon inscribed in a circle. This can also be described as a…

Illustration of a cyclic quadrilateral, a quadrilateral inscribed in a circle. This can also be described as a circle circumscribed about a quadrilateral. In this illustration, the quadrilateral is not regular (the lengths of the sides are not equal).

Cyclic Quadrilateral

Illustration of a cyclic quadrilateral, a quadrilateral inscribed in a circle. This can also be described…

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle circumscribed about a hexagon. In this illustration, the hexagon is not regular (the lengths of the sides are not equal).

Cyclic Hexagon

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle…

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle circumscribed about a hexagon. In this illustration, the hexagon is not regular (the lengths of the sides are not equal).

Cyclic Hexagon

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle…

Illustration of a hexagon in a circle. Four of the six vertices of the hexagon are bound by the circle (are tangent to the circle). Because all six vertices are not on the circle, the hexagon is not cyclic; it is not inscribed in the circle.

Hexagon In A Circle

Illustration of a hexagon in a circle. Four of the six vertices of the hexagon are bound by the circle…

Illustration of a 5-point star inscribed in a circle. This can also be described as a circle circumscribed about a 5-point star.

Star Inscribed In A Circle

Illustration of a 5-point star inscribed in a circle. This can also be described as a circle circumscribed…

Illustration of a 6-point star created by two equilateral triangles (often described as the Star of David) inscribed in a circle. This can also be described as a circle circumscribed about a 6-point star, or two triangles.

Star Inscribed In A Circle

Illustration of a 6-point star created by two equilateral triangles (often described as the Star of…

Illustration of a 6-point star (convex dodecagon) inscribed in a circle. This can also be described as a circle circumscribed about a 6-point star, or convex dodecagon.

Star Inscribed In A Circle

Illustration of a 6-point star (convex dodecagon) inscribed in a circle. This can also be described…

Illustration of a 6-point star (convex dodecagon) inscribed in a large circle and circumscribed about a smaller circle.

Star Inscribed And Circumscribed About Circles

Illustration of a 6-point star (convex dodecagon) inscribed in a large circle and circumscribed about…

Illustration of a 6-point star (convex dodecagon) circumscribed about a circle. This can also be described as a circle inscribed in a 6-point star, or convex dodecagon.

Star Circumscribed About A Circle

Illustration of a 6-point star (convex dodecagon) circumscribed about a circle. This can also be described…

Illustration of an 8-point star, created by two squares at 45° rotations, inscribed in a circle. This can also be described as a circle circumscribed about an 8-point star, or two squares.

Star Inscribed In A Circle

Illustration of an 8-point star, created by two squares at 45° rotations, inscribed in a circle.…

Illustration of an 8-point star, or convex polygon, inscribed in a circle. This can also be described as a circle circumscribed about an 8-point star.

Star Inscribed In A Circle

Illustration of an 8-point star, or convex polygon, inscribed in a circle. This can also be described…

Illustration of an 8-point star (convex polygon) inscribed in a large circle and circumscribed about a smaller circle.

Star Inscribed And Circumscribed About Circles

Illustration of an 8-point star (convex polygon) inscribed in a large circle and circumscribed about…

Illustration of an 8-point star (convex polygon) circumscribed about a circle. This can also be described as a circle inscribed in an 8-point star, or convex polygon.

Star Circumscribed About A Circle

Illustration of an 8-point star (convex polygon) circumscribed about a circle. This can also be described…

Illustration of a triangle with its incircle and three excircles constructed.

Triangle With Circle Constructions

Illustration of a triangle with its incircle and three excircles constructed.

For larger circles beam compasses are used. The two parts called channels which carry the pen and the needle point are clamped to a wooden beam at a distance equal to the radius of the circle. The thumb nut underneath one of the channel pieces makes accurate adjustment possible.

Beam Compasses

For larger circles beam compasses are used. The two parts called channels which carry the pen and the…

Circle pattern exercise: Draw diagonals A C and D B, and with the T-square draw the line E H. Now mark off on E H distances of 1.4 inch, and with H as a center describe, by means of the compasses, circles having radii respectively 2 inches, 1.5 inches, 1 inch, 0.75 inch, 0.5 inch, and .25 inch. Similarly with H as a center and a radius of 1.75 inch and 1.25 inches respectively raw the arcs F G and I J and K L and M N, being careful to end the arcs in the diagonals.

Circle Exercise

Circle pattern exercise: Draw diagonals A C and D B, and with the T-square draw the line E H. Now mark…

Always draw a circle in one stroke, inclining the compass in the direction of the line and rolling the handle between the thumb and finger.

Inking a Circle

Always draw a circle in one stroke, inclining the compass in the direction of the line and rolling the…

"Hands on hips. Twist the trunk around in a circle, first one way, then the other." -Foster, 1921

Exercise

"Hands on hips. Twist the trunk around in a circle, first one way, then the other." -Foster, 1921

"Tense the muscles of the neck and turn head... forward and back and around in a circle." -Foster, 1921

Exercise

"Tense the muscles of the neck and turn head... forward and back and around in a circle." -Foster, 1921

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

Exercise

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

Exercise

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

A little girl sitting among flowers. The circle is bordered with hand games and images of playing.

Girl

A little girl sitting among flowers. The circle is bordered with hand games and images of playing.

A man exercising with the quarter circle used for chest and arms.

Quarter Circle

A man exercising with the quarter circle used for chest and arms.

These diagrams show that the bigger the circle or sphere, the more space in between.

Spheres

These diagrams show that the bigger the circle or sphere, the more space in between.

A caliper used for measuring the diameter of a circle.

Caliper

A caliper used for measuring the diameter of a circle.

"The inner circle incloses a map upon which the horizontal direction of the lower currents is shown by unbroken arrows, and that of the upper currents by broken arrows. The map is surrounded by a vertical section of the atmosphere in which the up-and-down are also shown by arrows. Near the equator the air rises and moves westward, and near the tropics it moves eastward and descends." -Dryer, 1901

Atmospheric Circulation

"The inner circle incloses a map upon which the horizontal direction of the lower currents is shown…

The diagram "shows the isotherms in a cyclone of, say, 500 miles in diameter, as indicated by the circle, along which also the direction of the wind is shown by means of arrows." -Waldo, 1896

Isotherms in a Cyclone

The diagram "shows the isotherms in a cyclone of, say, 500 miles in diameter, as indicated by the circle,…

Illustration of a circle divided in half.

Circle, 1/2 Fraction

Illustration of a circle divided in half.

Illustration of a circle divided into thirds. One third is shaded.

1/3 Circle

Illustration of a circle divided into thirds. One third is shaded.

Illustration showing the definition of a circle as a conic section. The section of a right circular cone made by a plane that is perpendicular to the axis (or parallel to the base).

Conic Section Showing A Circle

Illustration showing the definition of a circle as a conic section. The section of a right circular…

"Diagram of Teleostean circulation. A., auricle; V., ventricle; v.a., ventral aorta; a.br., afferent branchials; e.br., efferent branchials; c.c., cephalic circle; e., carotids; A.c.v., anterior cardinal veins; P.C.V., posterior cardinal veins; d.c., ductuss Cuvieri; d.a., dorsal aortaa; c.v., caudal vein; c.a., caudal artery; K., kidney." -Thomson, 1916

Teleostean Circulation

"Diagram of Teleostean circulation. A., auricle; V., ventricle; v.a., ventral aorta; a.br., afferent…

View of the heart with its several chambers exposed and the vessels in connection with them. Labels: 1, the superior vena cava. 2, the inferior vena cava. 3. the chamber called the auricle. 4. the right ventricle. 5. the line marking the passage between the two chambers, and the points of attachment of one margin of the valve. 6. the septum between the two ventricles. 7. the pulmonary artery, arising from the right ventricle, and dividing at 8 into right and left, of the corresponding lungs. 9. the four pulmonary veins, bringing the blood from the lungs into 10, the left auricle. 11. the left ventricle. 12. the aorta, arising from the left ventricle, and passing down behind the heart, to distribute blood to every part of the system. Thus the blood moves in a double circle, one from the heart to the body, and from the body back to the heart, called the systemic circle; the other, from the heart to the lung, and from the lung back to the heart, called the pulmonic circle.

Heart and its Chambers

View of the heart with its several chambers exposed and the vessels in connection with them. Labels:…

Illustration showing a circle with a radius of 2 in. intersecting a circle with a radius of 3 in..

2 Intersecting Circles

Illustration showing a circle with a radius of 2 in. intersecting a circle with a radius of 3 in..

Illustrations used to construct an ellipse. Fig. 59 shows a compass at C used to strike a circle. Where the circle intersects the line at D and B, place pins. These pins represent the foci of the ellipse. Use a cord and a pencil to draw the ellipse as shown in figure 60. This illustrates the definition of an ellipse.

Construction Of An Ellipse

Illustrations used to construct an ellipse. Fig. 59 shows a compass at C used to strike a circle. Where…

"A circle may be considered as made up of triangles whose bases form the circumference, and whose altitude is the radius (1/2 diameter) of the circle." This is clearly shown by the cut at the left.

Circle Made Up Of Triangles

"A circle may be considered as made up of triangles whose bases form the circumference, and whose altitude…

An illustration of a circle inscribed in a square. It can be used to show that the area of a circle is .7854 of the area of a square whose sides are equal to its diameter.

Circle Inscribed In A Square

An illustration of a circle inscribed in a square. It can be used to show that the area of a circle…

A circle with labels for radius, diameter, and circumference. The visual will help to remember what each term means.

Circle Parts

A circle with labels for radius, diameter, and circumference. The visual will help to remember what…

A pie graph of "Proportion of World's Supply of Cotton contributed by each country" labeled with country names and percentages.

Pie Graph

A pie graph of "Proportion of World's Supply of Cotton contributed by each country" labeled with country…

"In the triangle above, the line AB is its altitude. Since we know how to find the area of one triangle, we can find the areas of as many triangles as we have made from our circle. Therefore, to find the area of a circle: Find the area of one of the triangles and multiply by the number of triangles." -Foster, 1921

Area of Circle with Triangles

"In the triangle above, the line AB is its altitude. Since we know how to find the area of one triangle,…

An illustration of an arc of a circle. An arc is any part of the circumference of a circle.

Arc of Circle

An illustration of an arc of a circle. An arc is any part of the circumference of a circle.

An illustration showing the intersection of a plane and a cone. The cone is intersected by a plane parallel to the base, forming a circle.

Conic Section Showing A Circle

An illustration showing the intersection of a plane and a cone. The cone is intersected by a plane parallel…

An illustration showing the construction used to divide a line AB into two equal parts; and to erect a perpendicular through the middle. "With the end A and B as centers, draw the dotted circle arcs with a radius greater than half the line. Through the crossings of the arcs draw the perpendicular CD, which divides the line into two equal parts."

Construction Of A Line Divided In Equal Parts

An illustration showing the construction used to divide a line AB into two equal parts; and to erect…

An illustration showing the construction used to erect a perpendicular. "With C as a center, draw the dotted circle arcs at A and B equal distances from C. With A and B as centers, draw the dotted circle arcs at D. From the crossing D draw the required perpendicular DC."

Construction Of A Perpendicular

An illustration showing the construction used to erect a perpendicular. "With C as a center, draw the…

An illustration showing the construction used to erect a perpendicular from a point to a line. "With C as a center, draw the dotted circle arc so that it cuts the line at A and B. With A and B as centers, draw the dotted cross arcs at D with equal radii. Draw the required perpendicular through C and crossing D."

Construction Of A Perpendicular

An illustration showing the construction used to erect a perpendicular from a point to a line. "With…

An illustration showing the construction used to erect a perpendicular at the end of a line. "With the point D as a center at a distance from the line, and with AD as radius, draw the dotted circle arc so that it cuts the line at E through E and D, draw the diameter EC: then join C and A, which will be the required perpendicular."

Construction Of A Perpendicular

An illustration showing the construction used to erect a perpendicular at the end of a line. "With the…

An illustration showing how to find the center of a circle which will pass through three given points A, B, and C. "With B as a center, draw the arc DEFG; and with the same radius and A as a center, draw the cross arcs D and F; also with C as a center, draw the cross arcs E and G. Join D and F, and also E and G, and the crossing o is the required center of the circle."

Find The Center Of A Circle Through 3 Points

An illustration showing how to find the center of a circle which will pass through three given points…

An illustration showing how to construct a square upon a given line. "With AB as radius and A and B as centers, draw the circle arcs AED and BEC. Divide the arc BE in two equal parts at F, and with EF as radius and E as center, draw the circle CFD. Join A and CB and D, C and D, which completes the required square."

Square Constructed Upon A Given Line

An illustration showing how to construct a square upon a given line. "With AB as radius and A and B…

An illustration showing how to construct a tangent to a circle through a given point in a circumference. "Through a given point A and center C, draw the line BC. With A as a center, draw the circle arcs B and C; with B and C as centers, draw the cross arcs D and E; then join D and E, which is the required tangent."

Construction Of Tangent To Circle

An illustration showing how to construct a tangent to a circle through a given point in a circumference.…

An illustration showing how to construct a tangent to a circle through a given point outside of a circumference. "Join A and C, and upon AC as a diameter draw the half circle ABC, which cuts the given circle at B. Join A and B, which is the required tangent."

Construction Of Tangent To Circle

An illustration showing how to construct a tangent to a circle through a given point outside of a circumference.…

An illustration showing how to construct a tangent circle to a circle with a given radius. "Through the given point C, draw the diameter AC extended beyond D: from C set off the given radius R to D; then D is the center of the required circle, which tangents the given circle at C."

Construction Of Circle Tangent To Circle

An illustration showing how to construct a tangent circle to a circle with a given radius. "Through…

An illustration showing how to construct a tangent circle to 2 given circles. "Join centers C and c of the given circles, and extend the line to D; draw the radii AC and ac parallel with one another. Join Aa, and extend the line to D. On CD as a diameter, draw the half circle CeD; on cD as a diameter, draw the half circle cfD; then the crossings e and f are tangenting points of the circles."

Construction Of Circle Tangent To 2 Circles

An illustration showing how to construct a tangent circle to 2 given circles. "Join centers C and c…