Question 17153
Perimeter implies the sum of sides.
Let the second side be X
Then if 1 side is 20 inches shorter, this side = X-20
The second side is 5 inches longer than the third=> The third side is smaller by 5 cms => X-5
Sum = 155
X+X-20+X-5 = 155
3x-25 = 155
3X = 155+25 
3X = 180
X = 60
The larger side is X = 60 inches