2016 · Q84
A circle of 3 m radius is divided into three areas by semicircles of radii 1 m and 2 m as shown in the figure above. The ratio of the three areas A, B and C will be
Elementary MathematicsMensuration
- A2 : 3 : 2
- B1 : 1 : 1
- C4 : 3 : 4
- D1 : 2 : 1
Explanation
Writing each of A, B, C as sums/differences of the semicircular areas ½π·3², ½π·2² and ½π·1², each region comes to 3π. That is one third of the whole circle's 9π. Hence A:B:C = 1:1:1, option B.