Finding the Circumference

Front

What is the circumference of a circle?

Back

The distance around a circle.

Front

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

Back

C = π·d

Front

What number represents π?

Back

3.14

Front

What does C represent in the formula C = π·d?

Back

Circumference.

Front

Find the circumference of a circle with a diameter of 10 cm.

Back

C = π·d = 3.14·10 = 31.4 cm.

Front

What is the diameter of a circle?

Back

The distance across the circle through its center.

Front

How is the radius of a circle related to the diameter?

Back

The radius is half of the diameter.

Front

What is the formula to find the diameter if the circumference is known?

Back

d = C/π.

Front

If the circumference of a circle is 62.8 cm, what is the diameter?

Back

d = C/π = 62.8/3.14 = 20 cm.

Front

What is the relationship between circumference and radius?

Back

C = 2π·r.