Answer:

Step-by-step explanation:
In right triangle XZW, the height WY is the geometric mean of segments ZY and XY.
Hence,

Divide 13 by 3.
If there is a remainder, keep that as fraction.
.
4 1/3
12/3=4
4= whole number
13-12=1
1/3
4 + 1/3 = 4 1/3
Your answer is 4 1/3