Area and Circumference of Circles

Front

What is the formula for finding the circumference of a circle using the radius?

Back

Circumference = 2 * π * r

Front

What is the formula for finding the area of a circle?

Back

Area = π * r²

Front

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

Back

Diameter = 2 * radius = 20 ft

Front

What is the formula for finding the circumference of a circle using the diameter?

Back

Circumference = π * d

Front

What is the value of π (pi) approximately?

Back

π ≈ 3.14

Front

How do you calculate the area of a circle with a radius of 5 cm?

Back

Area = π * (5 cm)² = 78.5 cm²

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 * radius

Front

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

Back

Radius = Circumference / (2 * π) = 5 cm

Front

What is the circumference of a circle with a diameter of 10 cm?

Back

Circumference = π * 10 cm ≈ 31.4 cm

Front

How do you find the area of a circle with a diameter of 12 cm?

Back

Area = π * (6 cm)² = 113.1 cm²