Circles

Front

What is the formula for the area of a circle?

Back

Area = π × r × r (or πr²)

Front

What do you get when you multiply the radius by 2?

Back

Diameter

Front

What is the diameter of a circle if the radius is 5 ft?

Back

Diameter = 2 × r = 10 ft

Front

What is the circumference of a circle?

Back

Circumference = 2 × π × r

Front

What is the radius of a circle if the diameter is 16 ft?

Back

Radius = ½ × d = 8 ft

Front

What is the space contained inside a circle called?

Back

Area

Front

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

Back

Radius = 5 ft

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius

Front

If you have a circle with a radius of 3 ft, what is the area?

Back

Area = π × 3 × 3 = 9π ft²

Front

What is the formula for the circumference of a circle?

Back

Circumference = π × d (or 2πr)