Question

the sides of a rectangular park are in the ratio 4:3 if it's area is 1728 m² find the cost of fencing it at ruppes 30 per metre

Answer 1

let the sides of the park be 4x and 3x

Area of the park = 1728
lenght × breadth = 1728
4x × 3x = 1728
12xsq = 1728
xsq = 1728/12
x = root 144
x = 12
therefore
lenght and breadth = 2×2×3 = 12
hence,
lenght = 4×12=48
breadth = 3×12=36

perimeter = 2(48+36)
= 2×84= 168 m

cost of fencing = rs(168×30)
=rs5040

hope it helped you

Answer 2

Given: The sides of a rectangular park are in the ratio 4:3 if its area is 1728 m².

To find: We have to find the cost of fencing it at rupees 30 per metre.

Solution:

The sides of a rectangular park are in the ratio 4:3 if its area is 1728 m².

So, let the sides of the rectangle be 4x and 3x.

Now the area of the rectangle will be-

$12 {x}^{2} = 1728 \\ {x}^{2} = 144 \\ x = 12$

Thus the sides of the rectangle are 12×3=36m and 12×4=48 m.

So, the perimeter of the rectangle is-

$2(36 + 48) = 72 + 96 \\ =16 8$

The cost of fencing at 30 per metre will be-

168×30=5040.

The cost of fencing is 5040 rupees.