Circumference

Front

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

Back

C = π·d, where C is the circumference and d is the diameter.

Front

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

Back

C = π·d = π·10 cm ≈ 31.42 cm.

Front

What is the relationship between diameter and radius?

Back

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

Front

If the radius of a circle is 5 m, what is the diameter?

Back

d = 2r = 2·5 m = 10 m.

Front

What does π (pi) represent in the context of circles?

Back

π (pi) is a constant approximately equal to 3.14, representing the ratio of the circumference to the diameter of a circle.

Front

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

Back

r = C / (2π).

Front

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

Back

C = 2πr = 2π·7 cm ≈ 43.98 cm.

Front

What is the diameter of a circle with a circumference of 62.83 cm?

Back

d = C / π = 62.83 cm / π ≈ 20 cm.

Front

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

Back

C = π·d = π·12 m ≈ 37.68 m.

Front

If a circle has a circumference of 31.4 cm, what is its radius?

Back

r = C / (2π) = 31.4 cm / (2π) ≈ 5 cm.