Basic Circle - Radius, Diameter, Circumference, Area

Front

What is the radius of a circle?

Back

The distance from the center of the circle to any point on its circumference.

Front

What is the diameter of a circle?

Back

A line segment that passes through the center of the circle and has its endpoints on the circle. It is twice the length of the radius.

Front

What is the circumference of a circle?

Back

The distance around the circle.

Front

What is the area of a circle?

Back

The space inside the circle, calculated using the formula A = πr², where r is the radius.

Front

If the radius of a circle is 10 cm, what is the diameter?

Back

20 cm.

Front

If the diameter of a circle is 30 inches, what is the radius?

Back

15 inches.

Front

What is the formula for calculating the circumference of a circle?

Back

C = πd or C = 2πr, where d is the diameter and r is the radius.

Front

What is the formula for calculating the area of a circle?

Back

A = πr², where r is the radius.

Front

If the radius of a circle is 5 meters, what is the area?

Back

78.54 square meters (using π ≈ 3.14).

Front

If the circumference of a circle is 31.4 meters, what is the radius?

Back

5 meters (using C = 2πr).