Answer:
The sides are 20 , 25 , 35
Explanation:
Let's take the numbers in the Ratio form as x is 4:5:7 will become as 4x + 5x + 7x
The perimeter of a Triangle = sum of three sides
= 4x + 5x + 7x = 80 cm
= 16x = 80 cm
= x = 80/16
= x = 5
So 4x = 4 × 5 = 20
5x = 5 × 5 = 25
7x = 7 × 5 = 35