Question

What is the diameter of a circle whose area is equal to the sum of the areas of two circles of radii 40cm and 9cm?

Answer 1

Area of the circle = sum of areas of 2 circles

πR² = π(40)² + π(9)²

πR² = π × (40² + 9)²

R² = 1600 + 81

R² = 1681

R = 41 cm.

Diameter of required circle = 41 × 2 = 82 cm