Area and Circumference of Circles

Front

What is the distance around a circle?

Back

Circumference

Front

What is the longest distance across a circle through its center?

Back

Diameter

Front

What is the distance from the center of a circle to any point on its circumference?

Back

Radius

Front

What is the formula to calculate the circumference of a circle?

Back

C = 2πr or C = πd

Front

What is the formula to calculate the area of a circle?

Back

A = πr²

Front

If the radius of a circle is 7 cm, what is its area?

Back

A = π(7)² = 153.94 cm²

Front

If the diameter of a circle is 10 m, what is its circumference?

Back

C = πd = π(10) = 31.42 m

Front

What is the area of a circle with a radius of 5 inches?

Back

A = π(5)² = 78.54 in²

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius

Front

If a circle has a circumference of 62.83 cm, what is its radius?

Back

r = C/(2π) = 62.83/(2π) = 10 cm