Question

The breadth of a rectangle field is 3/7times of its length.Find the dimensions of the rectangular field,if its perimeter is 140 m

Answer 1

$\bold{given : } \\ \\ \bold{breadth \: of \: a \: rectangle :} \\ \\ \frac{3}{7} \times length \: \\ \\ \bold{perimeter \: of \: that \: field : } \\ \\ 140 \: m \: \\ \\ \\ \\ \bold{let : } \\ \\ \bold{length \: of \: that \: field : } \\ \\ l \: m \: \\ \\ \bold{breadth \: of \: that \: field :} \\ \\ \frac{3}{7} \times l \\ \\ \\ \\ \bold{perimeter \: of \: a \: rectangle : } \\ \\ \bold{2(l + b)}$
$\bold{140 =2 ( l + \frac{3}{7} \times l) }\\ \\ \frac{140}{2} = l + \frac{3}{7} \times l \\ \\ 70 = \frac{7 }{7} \times l + \frac{3}{7} \times \: l \\ \\ 70 = \frac{7 + 3}{7} \times l\\ \\ 70 \times 7 = 13 \times l\\ \\ 490 = 10 \times l \\ \\ l = \frac{490}{10} \\ \\\bold{ length = 49 \: m \: }\\ \\ \\ \\\bold{ breadth : } \\ \\ \frac{3}{7} \times l \\ \\ \frac{3}{7} \times 49 \\ \\\bold{breadth \: = 21 \: m \: }$