Circumference and Area of Circles

What is the formula for calculating the circumference of a circle?

• C = 2 * π * r

• C = π * r^2

• C = π * d

• C = 2 * r

If the radius of a circle is 7 cm, what is its circumference?

• Approximately 50.24 cm

• Approximately 31.42 cm

• Approximately 43.98 cm

• Approximately 21.99 cm

Calculate the circumference of a circle with a diameter of 10 m.

• 40.84 m

• 31.42 m

• 15.70 m

• 25.12 m

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

• A = 2πr

• A = πd

• A = r²/2

• A = πr²

If the radius of a circle is 5 cm, what is its area?

• 15π cm²

• 20π cm²

• 30 cm²

• 25π cm²

Calculate the area of a circle with a diameter of 8 m.

• 16π m²

• 24 m²

• 32π m²

• 12 m²

A circular garden has a radius of 4 m. What is the circumference of the garden?

• 8 m

• 8π m

• 16 m

• 12π m

A pizza has a radius of 10 inches. What is the area of the pizza?

• 50π square inches

• 200π square inches

• 100π square inches

• 75π square inches

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

• 10 cm

• 3 cm

• 5 cm

• 7 cm

A circular swimming pool has a diameter of 12 ft. What is its area?

• 48π ft²

• 18π ft²

• 24π ft²

• 36π ft²