Circle: Parts, Circumference & Area

Front

What is the area of a circle?

Back

The amount of space inside of the circle.

Front

What is the circumference of a circle?

Back

The distance around a circle.

Front

What is the radius of a circle?

Back

The distance from the center of the circle to any point on its circumference.

Front

What is the diameter of a circle?

Back

A line segment that passes through the center of the circle and has its endpoints on the circle.

Front

What is the formula for the area of a circle?

Back

Area = π × r², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × r, where r is the radius.

Front

If the radius of a circle is 9 cm, what is the area?

Back

Area = π × (9 cm)² ≈ 254.5 cm².

Front

If the diameter of a circle is 18 cm, what is the radius?

Back

Radius = Diameter / 2 = 18 cm / 2 = 9 cm.

Front

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

Back

Radius = Circumference / (2 × π) ≈ 5 mm.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius.