Question

The circumference of 2 circles are 924 cm and 616cm. Find the ratio of the area of 2 circles.
1. 5 ∶ 4
2. 7 ∶ 4
3. 9 ∶ 4
4. 11 ∶ 4

Answer 1

Correct Answer - Option 3 : 9 ∶ 4

Given:

Circumference of circle 1 = 924 cm

Circumference of circle 2 = 616 cm

Formula Used:

Circumference of circle = 2πr

Area of circle = πr²

Calculation:

Circumference of circle = 2πr

Circumference of circle 1 = 2πr

⇒ 924 cm = 2πr

⇒ r 1 = 147 cm

Circumference of circle 2 = 2πr

⇒ 616 cm = 2πr

⇒ r 2 = 98 cm

Area of circle 1 ∶ Area of circle 2

⇒ π (147)² ∶ π (98)²

⇒ 9 ∶ 4

∴ The ratio of the area of 2 circles is 9 ∶ 4.

The correct option is 3 i.e. 9 ∶ 4