Answer:
100
Explanation:
y is the length from top left to the shaded line from the top
z is the length from top left to the shaded line from the bottom
the shaded line = 48 (we are using Pythagoras theorem in this step and all the following ones)
48²+y²=z²
z²+60²=x²
48²+y²+60²=x²
x=y+36
48²+60²=72y+1296
y=64
x=100