Question

Find the radius of a circle whose area is equal to the sum of the areas of three circles whose radii are 3cm 4cm and 12cm

Answer 1

area of the circle =530.66 cm^2
radius = 13 cm

Answer 2

Radius of the bigger circle is approximately 13 cm.

Given data :

Radii of smaller circles = 3cm , 4cm and 12cm

Area of first smaller circle = π × (3)² = 22/7 × 9 = 28.28 cm²

Area of the second smaller circle = π × (4)² = 22/7 × 16 = 50.28 cm²

Area of the third smaller circle = π × (12)² = 22/7 × 144 = 452.57 cm²

So,area of the bigger circle = (28.28+50.28+452.57) = 531.13 cm²

Let,the radius of bigger circle = r cm

So,

πr² = 513.13

r² = 513.13×7/22

r² = 168.99

r = 12.99

r = 13 (approx) (answer)