Question

The sides of rectangular park are in ratio 4:3. If its area is 1728 m square . Find the cost of fencing it at 30 rupees per meter

Answer 1

Let the length be 4x and breadth be 3x
Area =length ×breadth
$1728 = 4x \times 3x = 12x {}^{2} \\ so \: x {}^{2} = 1728 \div 12 = 144 \\ then \: x = \sqrt{144} \: = 12 \\ length \: = 48m \: and \: breadth = 36m \\ perimeter = 2(48 + 36) = 2 \times 84 = 168m \\ so \: cost = 16 \times 168 = rs \: 2688$

Answer 2

Hey there!!!

Let 4x and 3x be the dimension of the rectangular park

According to the question -

$= > 4x \times 3x \: = 1728 \\ = > {12} {x} ^{2} = 1728 \: {m}^{2} \\ = > {x}^{2} = 144 \\ = > x \: = \sqrt{144} \\ = > x = 12$

L = 4x => 4 ×12 = 48

B = 3x => 3 × 12 = 36

Perimeter = 2( l+ b)

= 2 ( 48+36)

= 168

cost = rate × perimeter

= 30 × 168

= ₹ 5040

Hope this helps u !!!