Front

What is the circumference of a circle?

Back

The distance around the circle, calculated using the formula C = π·d or C = 2·π·r.

Front

What does 'r' represent in the formula C = 2·π·r?

Back

Radius, which is the distance from the center of the circle to any point on its circumference.

Front

What is the relationship between diameter and radius?

Back

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

Front

What is the formula to find the diameter if you know the circumference?

Back

d = C/π.

Front

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

Back

10 in.

Front

If the diameter of a circle is 20 ft, what is the radius?

Back

10 ft.

Front

What is π (pi)?

Back

A mathematical constant approximately equal to 3.14, used in calculations involving circles.

Front

How do you calculate the circumference of a circle with a radius of 10 cm?

Back

C = 2·π·10 cm ≈ 62.83 cm.

Front

What is the diameter of a circle with a radius of 25 mm?

Back

50 mm.

Front

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

Back

5 cm (C = 2·π·r, so r = C/(2·π)).