Area & Circumference of Circles

Front

What is the formula for the area of a circle given the radius?

Back

A = πr²

Front

What is the formula for the circumference of a circle given the radius?

Back

C = 2πr

Front

What is the formula for the area of a circle given the diameter?

Back

A = π(d/2)² or A = π(d²/4)

Front

What is the formula for the circumference of a circle given the diameter?

Back

C = πd

Front

If a circle has a radius of 7 meters, what is its area?

Back

A = π(7)² = 153.86 m²

Front

If a circle has a radius of 10 cm, what is its circumference?

Back

C = 2π(10) = 62.83 cm

Front

What is the area of a circle with a radius of 5 inches?

Back

A = π(5)² = 78.54 in²

Front

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

Back

r = √(A/π)

Front

If a storm affects a circle with a radius of 7 miles, what is the area affected?

Back

A = π(7)² = 153.86 mi²

Front

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

Back

A = π(4)² = 50.27 cm²