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…

Circle with secant and tangent drawn.

Circle With Tangent and Secant

Circle with secant and tangent drawn.

Illustration of a circle with a tangent drawn - a straight line perpendicular to a radius at its extremity.

Circle With Tangent Line Drawn

Illustration of a circle with a tangent drawn - a straight line perpendicular to a radius at its extremity.

Circle with triangle to show how to divide a line in extreme and mean ratio.

Circle and Triangle

Circle with triangle to show how to divide a line in extreme and mean ratio.

Circle with triangles.

Circle and Triangles

Circle with triangles.

Circle with triangle and chords.

Circle and Triangle

Circle with triangle and chords.

Circle with triangle and chords.

Circle and Triangle

Circle with triangle and chords.

Circle with triangle and chords.

Circle and Triangle

Circle with triangle and chords.

Illustration of an equilateral triangle circumscribed about a circle. This can also be described as a circle inscribed in an equilateral triangle.

Triangle Circumscribed About A Circle

Illustration of an equilateral triangle circumscribed about a circle. This can also be described as…

Circle with triangle inscribed.

Circle and Inscribed Triangle

Circle with triangle inscribed.

Illustration of triangle inscribed in circle. Or, circle circumscribed about triangle.

Triangle Inscribed in Circle

Illustration of triangle inscribed in circle. Or, circle circumscribed about triangle.

Illustration of an equilateral triangle inscribed in a circle. This can also be described as a circle circumscribed about an equilateral triangle.

Triangle Inscribed In A Circle

Illustration of an equilateral triangle inscribed in a circle. This can also be described as a circle…

An illustration showing a triangle with sides b, c, and d inscribed in a circle with radius r.

Triangle Inscribed In A Circle

An illustration showing a triangle with sides b, c, and d inscribed in a circle with radius r.

An illustration showing a triangle with angles A, C, and D inscribed in a circle which is tangent to a line.

Triangle Inscribed In A Circle

An illustration showing a triangle with angles A, C, and D inscribed in a circle which is tangent to…

Illustration showing a circle with an inscribed triangle and radii.

Circle With Inscribed Triangle and Radii

Illustration showing a circle with an inscribed triangle and radii.

Circle with two triangles.

Circle and Triangles

Circle with two triangles.

Illustration showing that a circle may be considered as made up of triangles whose bases form the circumference.

Triangles Making Up A Circle

Illustration showing that a circle may be considered as made up of triangles whose bases form the circumference.

Illustration of a circle with two intersecting chords within the circumference. The angle formed is measured by half the sum of the intercepted arcs.

Circle With Two Intersecting Chords

Illustration of a circle with two intersecting chords within the circumference. The angle formed is…

Illustration of a circle which illustrates that the tangents to a circle drawn from an external point are equal, and make equal angles with the line joining the point to the center.

Circle With Two Tangents Drawn From an External Point

Illustration of a circle which illustrates that the tangents to a circle drawn from an external point…

Illustration of a circle with unequal chords, which are unequally distant from the center.

Circle With Unequal Chords

Illustration of a circle with unequal chords, which are unequally distant from the center.

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. The circle is divided into four quadrants by the x- and y- axes. The circle can be labeled and used to find the six trigonometric values (sin, cos, tan, cot, sec, csc, cot) at each of the quadrantal angles.

Unit Circle

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. The…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. All quadrantal angles are given in radian measure in terms of pi.

Unit Circle Labeled At Quadrantal Angles

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. All quadrantal angles and angles that have reference angles of 30°, 45°, and 60° are given in radian measure in terms of pi. At each quadrantal angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled At Special Angles

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. All quadrantal angles and angles that have reference angles of 30°, 45°, and 60° are given in radian measure in terms of pi.

Unit Circle Labeled At Special Angles

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. At 30° increments, the angles are given in both radian and degree measure. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled In 30° Increments With Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. The circle is marked and labeled in both radians and degrees in 45° increments. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled In 45 ° Increments

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. At 45° increments, the angles are given in both radian and degree measure. At each quadrantal angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled In 45° Increments With Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. At 45° increments, the angles are given in both radian and degree measure. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled In 45° Increments With Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. All quadrantal angles are given in radian measure in terms of pi.  At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Quadrantal Angles And Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. All…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. All quadrantal angles are given in degree measure. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Quadrantal Angles And Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. All quadrantal angles are given in both radian and degree measure. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Quadrantal Angles And Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. At each quadrantal angle, the coordinates are given, but not the angle measure. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Quadrantal Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. At each…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. At each quadrantal angle, the coordinates are given, but not the angle measure. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Quadrantal Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. The circle is marked and labeled in radians. All quadrantal angles and angles that have reference angles of 30°, 45°, and 60° are given in radian measure in terms of pi. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Special Angles And Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. The circle is marked and labeled in both radians and degrees at all quadrantal angles and angles that have reference angles of 30°, 45°, and 60°. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Special Angles And Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with the x- and y-axes indicated. The circle is marked and labeled in both radians and degrees at all quadrantal angles and angles that have reference angles of 30°, 45°, and 60°. At each angle, the coordinates are given. These coordinates can be used to find the six trigonometric values/ratios. The x-coordinate is the value of cosine at the given angle and the y-coordinate is the value of sine. From those ratios, the other 4 trigonometric values can be calculated.

Unit Circle Labeled With Special Angles And Values

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane with…

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. All quadrantal angles and angles that have reference angles of 30°, 45°, and 60° are marked from the origin, but no values are given.

Unit Circle Marked At Special Angles

Illustration of a unit circle (circle with a radius of 1) superimposed on the coordinate plane. All…

Illustration showing a circle with various chords drawn.

Circle With Various Chords

Illustration showing a circle with various chords drawn.

Illustration showing a circle with various chords drawn.

Circle With Various Chords

Illustration showing a circle with various chords drawn.

Illustration showing a circle with various chords and tangents drawn.

Circle With Various Chords And Tangents

Illustration showing a circle with various chords and tangents drawn.

Illustration showing a circle with various chords and tangents drawn.

Circle With Various Chords And Tangents

Illustration showing a circle with various chords and tangents drawn.

Illustration showing an equilateral triangle inscribed in a circle.

Circle With Inscribed Equilateral Triangle

Illustration showing an equilateral triangle inscribed in a circle.

Illustration showing a circle with an inscribed and circumscribed quadrilateral.

Circle With Inscribed and Circumscribed Quadrilaterals

Illustration showing a circle with an inscribed and circumscribed quadrilateral.

Illustration showing a circle with an inscribed quadrilateral and triangles formed by extended chords.

Circle With Inscribed Quadrilateral and Triangles Formed

Illustration showing a circle with an inscribed quadrilateral and triangles formed by extended chords.

Circles in a perspective drawing.

Circles

Circles in a perspective drawing.

Circular rosette-like pattern made with 12 overlapping congruent circles tangent to a center circle and an outer circle.

12 Overlapping Circles About a Center Circle and Inside a Larger Circle

Circular rosette-like pattern made with 12 overlapping congruent circles tangent to a center circle…

Illustration of two circles that are externally tangent to each other.

2 Externally Tangent Circles

Illustration of two circles that are externally tangent to each other.

Illustration of two circles that are internally tangent to each other.

2 Internally Tangent Circles

Illustration of two circles that are internally tangent to each other.

Circular rosette-like pattern made with 24 overlapping congruent circles tangent to a center circle and an outer circle.

24 Overlapping Circles About a Center Circle and Inside a Larger Circle

Circular rosette-like pattern made with 24 overlapping congruent circles tangent to a center circle…

A large circle containing 3 smaller congruent circles. The small circles are externally tangent to each other and internally tangent to the larger circle.

3 Smaller Circles In A Larger Circle

A large circle containing 3 smaller congruent circles. The small circles are externally tangent to each…

A large circle containing 3 smaller congruent circles. The small circles are externally tangent to each other and internally tangent to the larger circle.

3 Smaller Circles In A Larger Circle

A large circle containing 3 smaller congruent circles. The small circles are externally tangent to each…

A large circle containing 4 smaller congruent circles. The small circles are externally tangent to each other and internally tangent to the larger circle.

4 Smaller Circles In A Larger Circle

A large circle containing 4 smaller congruent circles. The small circles are externally tangent to each…

A large circle containing 4 smaller congruent circles. The small circles are externally tangent to each other and internally tangent to the larger circle.

4 Smaller Circles In A Larger Circle

A large circle containing 4 smaller congruent circles. The small circles are externally tangent to each…

Circular rosette-like pattern made with 48 overlapping congruent circles tangent to a center circle and an outer circle.

48 Overlapping Circles About a Center Circle and Inside a Larger Circle

Circular rosette-like pattern made with 48 overlapping congruent circles tangent to a center circle…

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 large circle containing 7 smaller congruent circles. The small circles are externally tangent to each other and internally tangent to the larger circle.

7 Smaller Circles In A Larger

A large circle containing 7 smaller congruent circles. The small circles are externally tangent to each…

A large circle containing 7 smaller congruent circles. The small circles are externally tangent to each other and internally tangent to the larger circle.

7 Smaller Circles In A Larger Circle

A large circle containing 7 smaller congruent circles. The small circles are externally tangent to each…

7 congruent circles. 6 of the circles are equally placed about the center circle. The circles are externally tangent to each other.

7 Tangent Circles

7 congruent circles. 6 of the circles are equally placed about the center circle. The circles are externally…

Illustration showing angles formed by two secants, two tangents, or a tangent and a secant, drawn to a circle form an external point. The angle is measured by half the difference of the intercepted arcs.

Circles With Angles Formed by Secants and Tangents

Illustration showing angles formed by two secants, two tangents, or a tangent and a secant, drawn to…

Illustration used to prove "If two circumferences meet at a point which is not on their line of centers, they also meet in one other point."

Circumferences of 2 Circles

Illustration used to prove "If two circumferences meet at a point which is not on their line of centers,…