Circumference of a Circle

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

What is the circumference of a circle with a radius of 3 cm?

Back

18.9 cm

Front

If a circle has a radius of 7.5 ft, what is its circumference?

Back

47.1 ft

Front

What is the circumference of a circle with a radius of 21 cm?

Back

131.9 cm

Front

What is the relationship between diameter and radius?

Back

Diameter is twice the radius (D = 2r).

Front

What is the circumference of a 12-inch pizza?

Back

37.68 inches

Front

What is the value of π (pi) approximately?

Back

π ≈ 3.14.

Front

How do you convert radius to diameter?

Back

Multiply the radius by 2.

Front

What is the circumference of a circle with a diameter of 10 cm?

Back

31.4 cm.

Front

What is the area of a circle with a radius of 5 cm?

Back

78.5 cm² (Area = πr²).