Angle P and angle Q are the same, which means the two sides PR and QR are the same.
Set the two equations to equal and solve:
5n = 32 +n
Subtract 1n from each side:
4n = 32
Divide both sides by 4:
n = 32 / 4
n = 8
Now we have the value for n, solve for PR.
PR = 5n = 5(8) = 40