Area of a rectangle is equal to the area of the circle whose radius is

1.	Area of a rectangle is equal to the area of the circle whose radius is 21 cms. If the length and the breadth of the rectangle are in the ratio of 14 : 11 respectively, what is its perimeter?1). 142 cms.2). 140 cms.3). 132 ems.4). 150 cms.
Answer» Solution Radius of circle = 21 cm => Area of circle = $\pi r^2$ = $\FRAC{22}{7} \times 21 \times 21 = 1386 cm^2$ Thus, area of rectangle = $1386 cm^2$ Let LENGTH and breadth of rectangle be $14x$ and $11x$ respectively. => Area = $14x \times 11x = 1386$ => $x^2 = \frac{1386}{154} = 9$ => $x = \SQRT{9} = 3$ cm $\therefore$ Perimeter = $2 (14x + 11x)$ = $2 \times 25x = 50x$ = $50 \times 3 = 150$ cm

Area of a rectangle is equal to the area of the circle whose radius is 21 cms. If the length and the breadth of the rectangle are in the ratio of 14 : 11 respectively, what is its perimeter?1). 142 cms.2). 140 cms.3). 132 ems.4). 150 cms.

Answer»

Solution

Radius of circle = 21 cm

=> Area of circle = $\pi r^2$

= $\FRAC{22}{7} \times 21 \times 21 = 1386 cm^2$

Thus, area of rectangle = $1386 cm^2$

Let LENGTH and breadth of rectangle be $14x$ and $11x$ respectively.

=> Area = $14x \times 11x = 1386$

=> $x^2 = \frac{1386}{154} = 9$

=> $x = \SQRT{9} = 3$ cm

$\therefore$ Perimeter = $2 (14x + 11x)$

= $2 \times 25x = 50x$

= $50 \times 3 = 150$ cm