Review Area of Circles

Front

What is the formula for the area of a circle?

Back

Area = π × r², where r is the radius.

Front

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

Back

Radius = Diameter / 2 = 10 cm / 2 = 5 cm.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius.

Front

How do you calculate the circumference of a circle?

Back

Circumference = π × Diameter.

Front

What is the value of π (pi) approximately?

Back

π ≈ 3.14.

Front

If a circle has a radius of 4 inches, what is its area?

Back

Area = π × (4 in)² = 50.24 in².

Front

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

Back

Circumference = 2 × π × 7 cm ≈ 43.96 cm.

Front

How do you find the area of a circle if you know the circumference?

Back

Area = (Circumference / 2π)² × π.

Front

What is the area of a circle with a radius of 10 m?

Back

Area = π × (10 m)² ≈ 314.16 m².

Front

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

Back

Diameter = Circumference / π = 31.4 cm / 3.14 = 10 cm.