ClipArt ETC
Illustration showing a cycloid curve. "The curve generated by a point in the plane of a circle when the circle is rolled along a straight line and always in the same plane."

Cycloid

Illustration showing a cycloid curve. "The curve generated by a point in the plane of a circle when…

Illustration showing cycloid curves. "The curve generated by a point in the plane of a circle when the circle is rolled along a straight line and always in the same plane."

Cycloids

Illustration showing cycloid curves. "The curve generated by a point in the plane of a circle when the…

Illustration showing a cycloid curve. "The curve generated by a point in the plane of a circle when the circle is rolled along a straight line and always in the same plane."

Cycloid

Illustration showing a cycloid curve. "The curve generated by a point in the plane of a circle when…

From Kipling's The Jungle Book, Baloo singing the Law of the Jungle to a pack of wolves.

Baloo Singing to Wolves

From Kipling's The Jungle Book, Baloo singing the Law of the Jungle to a pack of wolves.

With the plane, one can make rough wood true, smooth and beautiful. The name plane, perhaps, comes from the work it does, for it is used to smooth or reduce wood to a true plane.

Circular Plane

With the plane, one can make rough wood true, smooth and beautiful. The name plane, perhaps, comes from…

"In geometry: (a) A plane figure inclosed between the arc of a circle, ellipse, or other central curve and two radii to its extremities from the center. Thus, in the figure, CDB is a sector of a circle." -Whitney, 1911

Sector

"In geometry: (a) A plane figure inclosed between the arc of a circle, ellipse, or other central curve…

The main entrance through the circuit wall was made grand by the best known feature of Mycenae, the Lion Gate, through which passed a stepped ramp leading past circle A and up to the palace. The Lion Gate was built in the form of a 'Relieving Triangle' to support the weight of the stones. Two lionesses flank the central column that represents a god or goddess.

Lion Gate at Mycenæ

The main entrance through the circuit wall was made grand by the best known feature of Mycenae, the…

An illustration depicting the formation of circles of diffusion. "From point A luminous rays enter the eye in the form of a cone, the kind of which will depend on the pupil. Thus it may be circular, or oval, or ever triangular. If the pencil is focused in front of the retina, as at d, or behind it as it as at f, or, in other words, if the retina of being at F; be in the position G or H, there will be a luminous circle or a luminous triangular space, and many elements of the retina will be affected. The size of these diffusion circles depends on the distance from the retina of the point where the rays are focused: the greater the distance, the more extended will be the diffusion circle" (Britannica, 132).

Formation of Circles of Diffusion

An illustration depicting the formation of circles of diffusion. "From point A luminous rays enter the…

Circular and polygonal plans appear in a number of Syrian examples of the early sixth century. Their most striking feature is the inscribing of the circle of polygon in a square which forms the exterior outline, and the use of four niches to fill out the corners. This occurs at Kelat Seman, a small double church, perhaps the tomb and chapel of a martyr; in the cathedral at Bozrah, and in the small domical church of St. George at Ezra. These were probably the prototypes of many Byzantine churches like St. Sergius at Constantinople, and San Vitale at Ravenna.

Cathedral at Bosra

Circular and polygonal plans appear in a number of Syrian examples of the early sixth century. Their…

Sexpartite vault (or six-part vault), in architecture, is a rib vault divided into six bays by two diagonal ribs and three transverse ribs. Legend: a, transverse ribs (doubleaux); b, wall-ribs (formerets); c, groin-ribs (diagonaux). All the ribs are semi-circle.

Sexpartite Ribbed Vault, Showing Two Compartments with the Fillings Complete

Sexpartite vault (or six-part vault), in architecture, is a rib vault divided into six bays by two diagonal…

"Inside Clinch -- The end is bent close round the standing part till it forms a circle and a half, when it is securely seized at a, b, and c, thus making a running eye; when taut round anything it jams the end. It is used for securing hemp cables to anchors, the standing parts of topsail sheets, and for many other purposes. If the eye were formed outside the bight an outside clinch would be made, depending entirely on the seizings, but more ready for slipping." -Britannica, 1910

Inside Clinch

"Inside Clinch -- The end is bent close round the standing part till it forms a circle and a half, when…

"Ground Plan of the Colosseum at Rome, with representation of the Tiers of Seats, and of the Substructure. The shape of the amphitheatre was borrowed from that of the theatre. Since no stage was necessary, and with a view to securing as many rows of seats as possible, the semicircular form of the theatre was done away with, and the whole became a circle, or rather an ellipse, which was afterwards the recognized shape for all buildings of this nature, whether at Rome or in the provinces."

Ground Plan of the Colosseum

"Ground Plan of the Colosseum at Rome, with representation of the Tiers of Seats, and of the Substructure.…

"In geometry, an angle connected with an ellipse and defined as ... angle BCL, reckoned from one determinate end, B, of the transverse axis, called the eccentric angle of the point H." -Whitney, 1911

Eccentric Angle

"In geometry, an angle connected with an ellipse and defined as ... angle BCL, reckoned from one determinate…

"In geometry, a curve generated by the motion of a point on the circumference of a circle which rolls upon the convex side of a fixed circle." -Whitney, 1911

Epicycloid

"In geometry, a curve generated by the motion of a point on the circumference of a circle which rolls…

"Epicycloidal wheel, a wheel or ring fixed to a framework, toothed on its inner side, and having in gear with it another toothed wheel, of half the diameter of the first, fitted so as to revolve about the center of the latter. It is used for converting circular into alternate motion, or alternate into circular." -Whitney, 1911

Epicycloidal Wheel

"Epicycloidal wheel, a wheel or ring fixed to a framework, toothed on its inner side, and having in…

Illustration showing complex numbers with a modulus equal to unity. The lines representing these numbers terminate in points lying on the circumference of a circle whose radius is unity.

Geometric Inspection of Complex Numbers

Illustration showing complex numbers with a modulus equal to unity. The lines representing these numbers…

Illustration of an angle &alpha with the vertex at the center, O, of a circle with radius OB. AC and BD are perpendicular to OB and join B with C. The are of the triangle OBC is less than the are of the sector OBC, and the sector OBC is less than the triangle OBD.

Triangles and Sectors in Quadrant I

Illustration of an angle &alpha with the vertex at the center, O, of a circle with radius OB. AC and…

Illustration of a right spherical triangle and the five circular parts placed in the sectors of a circle in the order in which they occur in the triangle. "The ten formulas used in the solution of spherical right triangles can be expressed by means of two rules, known as Napier's rules of circular parts."

Napier's Right Spherical Triangle

Illustration of a right spherical triangle and the five circular parts placed in the sectors of a circle…

The Italian Renaissance lunette panel is a semi-circle design found on a door-head.

Italian Renaissance Lunette Panel

The Italian Renaissance lunette panel is a semi-circle design found on a door-head.

The Arabian lunette panel is a semi-circle design found on a door-head.

Arabian Lunette Panel

The Arabian lunette panel is a semi-circle design found on a door-head.

Wrought-iron grill lunette panel. Its a semi-circle design typically found on a door-head.

Wrought-Iron Grill Lunette Panel

Wrought-iron grill lunette panel. Its a semi-circle design typically found on a door-head.

The mosaic circle pattern is inlaid pieces of stone, wood, glass, leather or straw to make a picture or pattern. This design is found in a cathedral in Monreale, Sicily, Italy.

Mosaic Square Pattern

The mosaic circle pattern is inlaid pieces of stone, wood, glass, leather or straw to make a picture…

The Arabian mosaic circle pattern is inlaid pieces of stucco on stone.

Arabian Mosaic Square Pattern

The Arabian mosaic circle pattern is inlaid pieces of stucco on stone.

Roman mosaic pattern of interlocking circles.

Roman Mosaic Circle Pattern

Roman mosaic pattern of interlocking circles.

This marble mosaic circle pattern is inlaid pieces of glass found in the windows of a cathedral in Florence, Italy.

Marble Mosaic Circle Pattern

This marble mosaic circle pattern is inlaid pieces of glass found in the windows of a cathedral in Florence,…

This geometrical circle pattern found in the St. Croce church in Florence, Italy.

Geometrical Pattern

This geometrical circle pattern found in the St. Croce church in Florence, Italy.

The marble mosaic circle pattern is inlaid pieces of stone, wood, glass, leather or straw to make a picture or pattern. This design is found in the San Vitale church in Ravenna, Italy.

Marble Mosaic Circle Pattern

The marble mosaic circle pattern is inlaid pieces of stone, wood, glass, leather or straw to make a…

The Arabian mosaic circle pattern is made out of stucco on stone.

Arabian Mosaic Stucco on Stone

The Arabian mosaic circle pattern is made out of stucco on stone.

The Moorish mosaic circle pattern is made out of stone and glazed terracotta. This design is found in the Alhambra palace in Granada, Spain.

Moorish Mosaic Pattern

The Moorish mosaic circle pattern is made out of stone and glazed terracotta. This design is found in…

This medieval tile pattern is a stained glass design. It the oldest process of fitting together pieces of colored glass in a mosaic style.

Medieval Tile Pattern

This medieval tile pattern is a stained glass design. It the oldest process of fitting together pieces…

This medieval tile circle pattern is a stained glass design. It the oldest process of fitting together pieces of colored glass in a mosaic style.

Medieval Tile Pattern

This medieval tile circle pattern is a stained glass design. It the oldest process of fitting together…

This Medieval Tile circle pattern is a stained glass design. It the oldest process of fitting together pieces of colored glass in a mosaic style.

Medieval Tile Pattern

This Medieval Tile circle pattern is a stained glass design. It the oldest process of fitting together…

This Medieval Tile circle pattern is a stained glass design. It the oldest process of fitting together pieces of colored glass in a mosaic style.

Medieval Tile Circle Pattern

This Medieval Tile circle pattern is a stained glass design. It the oldest process of fitting together…

This medieval tile circle pattern is a stained glass design. It the oldest process of fitting together pieces of colored glass in a mosaic style.

Medieval Tile Circle Pattern

This medieval tile circle pattern is a stained glass design. It the oldest process of fitting together…

This medieval tile circle pattern is a stained glass design. It the oldest process of fitting together pieces of colored glass in a mosaic style.

Medieval Tile Circle Pattern

This medieval tile circle pattern is a stained glass design. It the oldest process of fitting together…

Illustration used to show how to find the center when given an arc and its radius.

Construction Of Center

Illustration used to show how to find the center when given an arc and its radius.

Illustration used to show how to pass a circumference through any three points not in the same straight line.

Construction Of Circumference

Illustration used to show how to pass a circumference through any three points not in the same straight…

Illustration used to show how to inscribe a square in a given circle.

Construction Of Square Inscribed In Circle

Illustration used to show how to inscribe a square in a given circle.

Illustration used to show how to inscribe a regular hexagon in a given circle.

Construction Of Hexagon Inscribed In Circle

Illustration used to show how to inscribe a regular hexagon in a given circle.

Illustration used to show how to inscribe a regular pentagon in a given circle.

Construction Of Pentagon Inscribed In Circle

Illustration used to show how to inscribe a regular pentagon in a given circle.

Illustration used to show how to inscribe a regular octagon in a given circle.

Construction Of Octagon Inscribed In Circle

Illustration used to show how to inscribe a regular octagon in a given circle.

Illustration used to show how to inscribe any regular polygon in a given circle.

Construction Of Polygon Inscribed In Circle

Illustration used to show how to inscribe any regular polygon in a given circle.

Illustration used to show how to "find an arc of a circle having a known radius, which shall be equal in length to a given straight line."

Construction Of Arc

Illustration used to show how to "find an arc of a circle having a known radius, which shall be equal…

Illustration used to show how to find a straight line of the same length as a given arc of a circle.

Construction Of Line Equal To Arc

Illustration used to show how to find a straight line of the same length as a given arc of a circle.

Illustration of a circle inside of a rectangle. The two figures have the same center.

Circle Inside Rectangle

Illustration of a circle inside of a rectangle. The two figures have the same center.

Illustration of a circle inside of 2 concentric rectangles whose vertices are connected by line segments.

Circle Inside Concentric Rectangles

Illustration of a circle inside of 2 concentric rectangles whose vertices are connected by line segments.

Illustration of a cylinder cut by a plane making an angle of 57° with the base.

Plane Intersecting A Cylinder

Illustration of a cylinder cut by a plane making an angle of 57° with the base.

"Eye-splice. A sort of eye or circle formed by splicing the end of a rope into itself. a, one strand stuck; b, all three strands stuck once; c, all three strands stuck three times (finished splicing)." -Whitney, 1911

Eye Splice in Three Steps

"Eye-splice. A sort of eye or circle formed by splicing the end of a rope into itself. a, one strand…

"One of an order of beings, the life-principles or geniuses or tutelary spirits of living beings, believed in and reverenced by the ancient Persians, adherents of the Zoroastrian religion. (Also) a name given ... to a symbol seen on monuments of ancient Persian origin, representing a winged circle, with or without a manlike figure in it, hovering over the head of a king or other person, and believed by some to represent his tutelary spirit." -Whitney, 1911

Feloher from Nineveh

"One of an order of beings, the life-principles or geniuses or tutelary spirits of living beings, believed…

"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle of a carriage. It is designed to support the fore part of the body while allowing it to turn freely in a horizontal plane." Today, the fifth wheel is used in coupling of trailers and towing trucks. -Whitney, 1911

Fifth Wheel

"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle…

"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle of a carriage. It is designed to support the fore part of the body while allowing it to turn freely in a horizontal plane." Today, the fifth wheel is used in coupling of trailers and towing trucks. -Whitney, 1911

Fifth Wheel

"Fifth wheel, a horizontal plate, bent to form a whole or part of a circle, placed on the forward axle…

Development of concentric ridges in synclines. A) a region with synclinal or canoe-shaped folds. B) The synclinal valley shown in A is replaced by a mountain because of the occurrence of a hard stratum in the center.

Concentric Ridges in Synclines

Development of concentric ridges in synclines. A) a region with synclinal or canoe-shaped folds. B)…

An illustration of men sitting in a circle talking.

Men Sitting in Circle

An illustration of men sitting in a circle talking.

An illustration of a group of women in a sewing circle.

Sewing Circle

An illustration of a group of women in a sewing circle.

A circle shape of a shield or escutcheon in heraldry.

Circular Shield

A circle shape of a shield or escutcheon in heraldry.

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

Nonagon Inscribed in a Circle

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

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

Circle Inscribed in a Nonagon

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

An illustration of a circle doodad.

Circle Doodad

An illustration of a circle doodad.

Diagram used to prove the theorem: "Every section of a sphere by a lane is a circle."

Sphere Cut By Plane

Diagram used to prove the theorem: "Every section of a sphere by a lane is a circle."

Diagram used to prove the theorem: "All points in the circumference of a circle of a sphere are equally distant from each of its poles."

Circumference of a Circle of a Sphere

Diagram used to prove the theorem: "All points in the circumference of a circle of a sphere are equally…