Area of Circles

Front

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

Back

A = πr², where A is the area and r is the radius.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius. d = 2r.

Front

If the radius of a circle is 3 m, what is its diameter?

Back

The diameter is 6 m.

Front

How do you convert diameter to radius?

Back

Divide the diameter by 2.

Front

What is the area of a circle with a radius of 4 cm?

Back

A = π(4)² = 50.27 cm².

Front

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

Back

A = π(5)² = 78.54 m².

Front

If a circle has an area of 154 cm², what is its radius?

Back

r = √(154/π) ≈ 7 cm.

Front

What is the area of a circle with a radius of 2.5 ft?

Back

A = π(2.5)² ≈ 19.63 ft².

Front

What is the area of a circle with a diameter of 12 inches?

Back

A = π(6)² ≈ 113.10 in².

Front

If the area of a circle is 314 cm², what is the diameter?

Back

d = 2√(314/π) ≈ 20 cm.