Subject: General Aptitude · Chapter: Area · Exam: · Marks: · Difficulty:
A circular wire of diameter 42 cm is bent in the form of a rectangle whose sides are in the ratio 6 : 5. The area of the rectangle is
(a)$540 \mathrm{cm}^{2}$
(b)$1080 \mathrm{cm}^{2}$
(c)$2160 \mathrm{cm}^{2}$
(d)$4320 \mathrm{cm}^{2}$
Answer
Answer (as printed): B
Explanation
Length of wire $=2 \pi R=\left(2 \times \frac{22}{7} \times 21\right) \mathrm{cm}=132 \mathrm{cm}$. Perimeter of rectangle $=2(6 x+5 x) \mathrm{cm}=22 x \mathrm{cm}$. $$\therefore \quad 22 x=132 \Leftrightarrow x=6 .$$ So, the sides of the rectangle are 36 cm and 30 cm. $$\therefore \quad \text { Area of the rectangle }=(36 \times 30) \mathrm{cm}^{2}=1080 \mathrm{cm}^{2} .$$