Question

Side of a rectangle are in the ratio 3:4 and it's area is 588sqcm find the perimeter of rectangle

Answer 1

Let the sides be 3k and 4k.
Area= length * breadth
588 = 3k * 4k = 12k^2
588/12 = k^2
49 = k^2
k = √49
k = 7
Now,
One side = 3k = 3 × 7 = 21 cm
Other side = 4k = 4 × 7 = 28cm
Now,
Perimeter = 2(length + breadth)
= 2(21 + 28) = 2× 49
= 98cm

Answer 2

Length of rectangle = L
Breadth of rectangle = b

According to question
L/b = 3/4

and
Lb = 588
(3/4)b^2 = 588 ……[∵ L = 3b/4]
b = sqrt(4 × 588/3)
b = 28 cm

L = 3 × 28 / 4 = 21 cm

Perimeter = 2 × (L + b)
= 2 × (21 + 28)
= 98 cm