circumference of a circle

Front

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

Back

C = 2πr or C = πd, where r is the radius and d is the diameter.

Front

What does the term 'circumference' refer to?

Back

The distance around a circle.

Front

If a circle has a diameter of 15 mm, what is its circumference?

Back

C = πd = π(15) ≈ 47.12 mm.

Front

What is the relationship between diameter and radius?

Back

The radius is half of the diameter (r = d/2).

Front

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

Back

C = 2π(10) = 20π ≈ 62.83 cm.

Front

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

Back

d = C/π = 31.4/π ≈ 10 cm.

Front

What is the circumference of a circular swimming pool with a diameter of 21 feet?

Back

C = πd = π(21) ≈ 65.94 feet.

Front

Which of the following is NOT a measurement related to circles?

Back

Area.

Front

What is the approximate value of π (pi)?

Back

π ≈ 3.14.

Front

If a circle has a circumference of 48 cm, what is its radius?

Back

r = C/(2π) = 48/(2π) ≈ 7.64 cm.