Mensuration Ques 2
Question
Circumference of a circle-A is $1 \frac{4}{7}$ times perimeter of a square. Area of the square is $784$ sq. cm. What is the area of another circle-B whose diameter is half the radius of the circle-A ?
(1) 38.5 sq.cm
(2) 156 sq.cm
(3) 35.8 sq.cm
(4) 616 sq.cm
(5) None of these
(IDBI Bank Officer Exam.16.09.2012)
Show Answer
Correct Answer: 5
Solution: (5)
Side of square $=\sqrt{784}$ $=28 cm$
$\therefore$ Circumference of circle A $=4 \times 28 \times \frac{11}{7}$
$\Rightarrow 2 \pi r=16 \pi$
$\Rightarrow 2 \times \frac{22}{7} \times r=16 \times 11$
$\Rightarrow r=\frac{16 \times 11 \times 7}{2 \times 22}=14$
Radius of circle- $r=\frac{28}{4}=7$
$\therefore$ Area $=\pi r^{2}$ $=\frac{22}{7} \times 7 \times 7=154$ sq.cm.
BETA
