Circumference of Circles

Front

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

Back

C = π·d or C = 2·π·r

Front

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

Back

5 inches

Front

What does the symbol π (pi) represent?

Back

Approximately 3.14, the ratio of the circumference of a circle to its diameter.

Front

How do you find the diameter if you know the radius?

Back

Diameter = 2 × Radius

Front

What is the circumference of a circle with a radius of 7 ft?

Back

43.96 ft (C = 2·π·7)

Front

If the circumference of a circle is 31.4 ft, what is the diameter?

Back

10 ft (C = π·d) => d = C/π

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius.

Front

If a circle has a radius of 15 cm, what is its diameter?

Back

30 cm

Front

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

Back

37.68 inches (C = π·12)

Front

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

Back

C represents the circumference of the circle.