Question 526225
Let
Length of second side = a = x
Length of first side = b = 2x
Length of third side = c = 3x 
Given
Perimeter of Triangle = P = 180cm



a+b+c=P
x+2x+3x=180
6x=180
x=180/6
x=30


Length of second side = a = x = 30 
Length of first side = b = 2x = 2(30) = 60
Length of third side = c = 3x = 3(30) = 90