Mensuration Ques 13
Question
The circumference of two circles is 88 metres and 220 metres respectively. What is the difference between the area of the larger circle and the smaller circle?
(1) 3422 sq. metre
(2) 3242 sq. metre
(3) 3244 sq. metre
(4) 3424 sq. metre
(5) None of these
(Corporation Bank PO Exam. 16.01.2011)
Show Answer
Correct Answer: (5)
Solution: (5)
$2 \pi r_{1}=88$
$\Rightarrow 2 \times \frac{22}{7} \times r_{1}=88$
$\Rightarrow r_{1}=\frac{88 \times 7}{2 \times 22}=14$ metre
$2 \pi r_{2}=220$
$\Rightarrow 2 \times \frac{22}{7} \times r_{2}=220$
$\Rightarrow r_{2}=\frac{220 \times 7}{2 \times 22}=35$ metre
Required difference $=\pi\left(r_{2}^{2}-r_{1}^{2}\right)$
$=\frac{22}{7}\left(r_{2}+r_{1}\right)\left(r_{2}-r_{1}\right)$
$=\frac{22}{7}(35+14)(35-14)$
$=\frac{22}{7} \times 49 \times 21=3234$ sq. metre
BETA
