Using the Pythagoras theorem formula, let us substitute the values in the equation: c2 = a2 + b2, where a = p, b = 15, c = 17. (Since hypotenuse is the longest side, we have taken c = 17)
c2 = a2 + b2
172 = p2 + 152
289 = p2 + 225
p2 = 64
p = 8
Therefore, the value of p = 8.