Mensuration Ques 3
Question
The circumference of a circular playground is 308 metre. There is 7 metre wide path around the ground. The area of the path is
(1) 2130 sq. metre
(2) 2410 sq. metre
(3) 2510 sq. metre
(4) 2310 sq. metre
(5) None of these
(Indian Overseas Bank PO Online Exam. 01.09.2013)
Show Answer
Correct Answer: (4)
Solution: (4)
$\Rightarrow 2 \pi r_{1}=308$ (where $r_{1}=$ radius of circular playground)
$\Rightarrow 2 \times \frac{22}{7} \times r_{1}=308$
$\Rightarrow r_{1}=\frac{308 \times 7}{2 \times 22}=49$ metre
$\Rightarrow$ New radius $\left(r_{2}\right)=49+7$ $=56 m$
$\therefore$ Area of the path $=\pi\left(r_{2}^{2}-r_{1}^{2}\right)$
$=\frac{22}{7}\left(56^{2}-49^{2}\right)$
$=\frac{22}{7}(56+49)(56-49)$
$=22 \times 105=2310$ sq. $m$.
BETA
