Question

the length of a rectangle is twice of its breadth if its perimeter of its 45 cm find area of rectangle

Answer 1

$suppose \: that \: breah = x$
therefore
$length = 2x$
we know that
$perimeter \: of \: rectangle = 45cm$
given that
$perimeter \: of \: rectangle = 2(length + breath)$
$2(x + 2x) = 45$
$6x = 45$
$x = 45 \times \frac{1}{6}$
we know that
$area \: of \: rectangle = l \times b$
therefore
$area = x \times 2x$
$area = 2x {}^{2}$
$area = 2 \times( 45 \times \frac{1}{6} ) {}^{2}$
$area = 2025 \times \frac{1}{18}$
$area = 112.5 \: cm {}^{2}$