Explanation:
The perimeter given can be used to find sides lengths because perimeter of a triangle is calculated by adding all three side lengths together
So x + 5 + x + 8 + x - 1 = 36 yd add the like terms
3x + 12 = 36 yd
3x = 24
x = 8
PQ = x + 8 ➡ 16
QR = x - 1 ➡ 7
PR = x + 5 ➡ 13