2016 · Q47
Two circles touch externally and sum of their areas is 130 π {cm}² and the distance between their centres is 14 cm. What is the difference in the radii of the circles ?
Elementary MathematicsCircles
- A5 cm
- B6 cm
- C7 cm
- D8 cm
Explanation
We have r₁+r₂ = 14 and r₁²+r₂² = 130. Then (r₁−r₂)² = 2(r₁²+r₂²)−(r₁+r₂)² = 260−196 = 64. So the difference of the radii is 8 cm (option D).