Area of Circles

Front

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

Back

A = πr²

Front

If a circle has a radius of 3 meters, what is its area?

Back

A = π(3)² = 28.27 m²

Front

What is the diameter of a circle if its radius is 5 cm?

Back

Diameter = 2 × Radius = 2 × 5 cm = 10 cm

Front

How do you calculate the radius from the area of a circle?

Back

Radius = √(Area/π)

Front

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

Back

A = π(5)² = 78.54 cm²

Front

What is the area of a semicircle with a diameter of 8 cm?

Back

A = (1/2) × π(4)² = 50.27 cm²

Front

What is the area of a circle with a radius of 7 inches?

Back

A = π(7)² = 153.94 in²

Front

If the area of a circle is 314.16 cm², what is its radius?

Back

Radius = √(314.16/π) ≈ 10 cm

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius

Front

How do you round the area of a circle to the nearest hundredth?

Back

Look at the third decimal place; if it's 5 or more, round up.