Parts of a Circle

Front

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

Back

Area = π r², where r is the radius.

Front

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

Back

Circumference = π d or Circumference = 2π r, where d is the diameter and r is the radius.

Front

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

Back

The radius is 5 ft.

Front

What is the diameter of a circle if the radius is 12 cm?

Back

The diameter is 24 cm.

Front

What do we call the distance around a circle?

Back

Circumference.

Front

What is the space contained inside a circle called?

Back

Area.

Front

If you multiply ½ × d, what do you get?

Back

Radius.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius.

Front

If the radius of a circle is 7 m, what is the area?

Back

Area = π (7)² = 49π m².

Front

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

Back

Diameter = 31.4 / π ≈ 10 m.