Circumference of Circles

Front

What is the formula for calculating the circumference of a circle?

Back

C = πd or C = 2πr, where C is circumference, d is diameter, r is radius, and π (pi) is approximately 3.14.

Front

If a circle has a diameter of 10 cm, what is its radius?

Back

The radius is half of the diameter, so the radius is 5 cm.

Front

How do you convert circumference to diameter?

Back

To find the diameter from the circumference, use the formula d = C/π.

Front

What is the relationship between diameter and radius?

Back

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

Front

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

Back

The diameter is 10 cm, calculated using d = C/π.

Front

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

Back

The circumference is 43.96 inches, calculated using C = 2πr.

Front

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

Back

Use the formula r = C/(2π).

Front

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

Back

The circumference is 37.68 feet, calculated using C = πd.

Front

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

Back

The diameter is 30 cm, calculated using d = 2r.

Front

What is the value of π (pi) used in calculations?

Back

π (pi) is approximately 3.14.