Answer:
x=9
Step-by-step explanation:
side opposite to 90 degree is hypotenuse(longest side of a triangle) . And other two are the legs of the triangle.
using pythagoras theorem
a^2 + b^2 = c^2
12^2 + x^2 = 15^2
144 + x^2 = 225
x^2 = 225 - 144
x^2 = 81
x = [tex]\sqrt{81}[/tex]
x = 9
