Parts of a Circle
This is the point at the exact middle of a circle.
Center
What is circumference?
The distance around a circle.
This is the amount of space inside a circle.
Area
A circle has a central angle of 80°. This is the measure of its intercepted minor arc.
80°
A circle has a central angle of 65°. This is the measure of its intercepted minor arc.
65°
A line segment that goes from the center of a circle to any point on the circle.
Radius
If a circle has a radius of 5, this is its circumference.
31.4
If a circle has a radius of 5, this is its area.
78.5
A circle has a radius of 6 and a central angle of 90°. This is the arc length.
9.4
A circle has a radius of 8 and a central angle of 45°. This is the area of the sector.
25.1
A line segment with both endpoints on the circle that passes through the center.
Diameter
If a circle has a diameter of 12, this is its circumference.
37.7
If a circle has a diameter of 14, this is its area.
153.9
A circle has a diameter of 10 and a central angle of 144°. This is the arc length.
12.6
A circle has a diameter of 18 and a central angle of 120°. This is the area of the sector.
84.8
A line segment with both endpoints on the circle that does not have to pass through the center.
Chord
A circle has a circumference of 56.5. This is its radius.
9.0
A circle has an area of 201.1 square units. This is its radius.
8.0
A circle has an arc length of 15.7 units and a central angle of 180°. This is the radius.
5.0
A circle has a sector area of 39.3 square units and a central angle of 90°. This is the radius.
7.1
This is a line that touches a circle at exactly one point.
Tangent
A circle has an area of 78.5 square units. This is its circumference.
31.4
A circle has a circumference of 43.96 units. This is its area.
153.9
A circle has an area of 78.5 square units and a central angle of 72°. This is the arc length.
6.3
A circle has a circumference of 62.8 units and a central angle of 144°. This is the area of the sector.
125.6