Circle Vocabulary and Circumference

Front

What is the value of pi?

Back

Approximately 3.14, but it is an infinite decimal.

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where C is the circumference and r is the radius.

Front

If the radius of a circle is 5 inches, what is the circumference?

Back

31.4 inches (C = 2π(5)).

Front

What is the definition of circumference?

Back

The distance around the edge of a circle.

Front

How many digits are in pi?

Back

Infinite.

Front

What is the radius of a circle?

Back

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

Front

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

Back

5 inches (r = d/2).

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius (d = 2r).

Front

What is the circumference of a circle with a diameter of 12 inches?

Back

Approximately 37.7 inches (C = πd).

Front

What is the diameter of a circle with a circumference of 31.4 inches?

Back

10 inches (d = C/π).