Question

if two adjacent sides of rectangle having perimeter 21 cm are in the ratio 3:4 what is the area of the rectangle is ...cm ?​

Answer 1

Let the length and breadth be l and b respectively.
Given,
l/b=3/4
=> l = 3b/4

We have,
P = 2(l+b)
=> 21 = 2(3b/4 + b)
=> 21*2= 7b
=> b = 6cm

Similarly,
l = 4.5cm
Thus, Area = l*b
=> Area = 4.5*6
=> Area = 27cm^2