Circles Unit Review

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius.

Front

How do you find the circumference of a circle?

Back

Circumference = πd, where d is the diameter.

Front

What is the relationship between diameter and radius?

Back

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

Front

If the radius of a circle is 5 cm, what is the area?

Back

Area = π(5)² = 25π cm².

Front

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

Back

Circumference = 2πr = 2π(7) = 14π cm.

Front

If the diameter of a circle is 10 inches, what is the radius?

Back

Radius = diameter/2 = 10/2 = 5 inches.

Front

What is the value of π (pi) approximately?

Back

π is approximately 3.14.

Front

How do you convert circumference to radius?

Back

Radius = Circumference / (2π).

Front

What is the area of a circle with a diameter of 8 inches?

Back

Area = π(4)² = 16π in².

Front

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

Back

Radius = Circumference / (2π) = 31.4 / (2π) = 5 cm.