Answer:
17.5
Explanation:
The perimeter is the sum of the side lengths:
perimeter = XZ +WZ +WX
The figure shows us WX = WZ, so we can rewrite the formula as ...
perimeter = XZ +2·WZ
Filling in the given values, this becomes ...
50 = 15 + 2·WZ
35 = 2·WZ
35/2 = WZ = 17.5
The length of WZ is 17.5 units.