Question

the perimeter of a triangle is 75 cm. if two of its sides are 20 cm and 30 cm , find the third side .

Answer 1

perimeter of a triangle is equal to sum of all side
75 is equal to 20 + 30 + x
75 is equal to 50 + x
x is equal to 75 - 50
x is equal to 25

Answer 2

Given-- Sides of ∆=20,30
Perimeter=75cm


Let it's third side be x.


P(∆)=a+b+c
75=20+30+x
75=50+x
75-50=x
25=x

Therefore, the third side is equal to 25cm.