Question

plz help me to answer the no.3 with formula picture

Answer 1

Let the length be 3x and the breadth be 7x.
Then we can say that
2*(3x+7x)=72
12x=36
X=3

Therefore the sides are 15 and 21

Answer 2

let sides be 5x and 7x...
the perimeter of parallelogram - sum of all sides.........
72 = 5x + 7x + 5x + 7x
72 = 10 x + 14 x
72 =24x
x = 72/24
x = 3
therefore sides are
5x = 5*3=15
7x = 7*3=21