Areas Related to Circles

Q. A circular garden has a diameter of 10 m. What is its area?

Solution

Radius = 10/2 = 5 m. Area = πr² = π(5)² = 25π ≈ 78.5 m².

Correct Answer: A — 78.5 m²

Q. A circular pond has a radius of 3 m. What is the area of the pond?

Solution

Area = πr² = π(3)² = 9π ≈ 28.26 m².

Correct Answer: C — 31.42 m²

Q. A circular table has a radius of 1.5 m. What is its area?

Solution

Area = πr² = π(1.5)² = 2.25π ≈ 7.07 m².

Correct Answer: A — 7.07 m²

Q. A circular track has a radius of 20 m. What is the area of the track?

Solution

Area = πr² = π(20)² = 400π ≈ 1256 m².

Correct Answer: A — 1256 m²

Q. If the area of a circle is 50.24 m², what is its radius?

Solution

Area = πr², r² = 50.24/π ≈ 16, r ≈ 4 m.

Correct Answer: B — 5 m

Q. If the radius of a circle is doubled, how does its area change?

Solution

Area = πr²; if r is doubled, area = π(2r)² = 4πr², so it quadruples.

Correct Answer: D — It quadruples

Q. What is the area of a circle with a circumference of 31.4 m?

Solution

Circumference = 2πr, r = 31.4/(2π) ≈ 5 m. Area = π(5)² = 25π ≈ 78.5 m².

Correct Answer: A — 78.5 m²

Q. What is the area of a circle with a radius of 10 cm?

Solution

Area = πr² = π(10)² = 100π ≈ 314 cm².

Correct Answer: A — 314 cm²

Q. What is the area of a circle with a radius of 7 cm?

Solution

Area = πr² = π(7)² = 49π ≈ 154 cm².

Correct Answer: A — 154 cm²

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