The sum of all the angles of a triangle is 180 degrees
We see that Line HI and JI are equal in length meaning that triangle HIJ is an isosceles triangle. This means that the two angles of unknown measure are both x.
So lets now set up our equation:
[tex]x + x + 74 = 180\\2x = 106\\x = 53[/tex]
Thus x is 53 degrees
Hope that helps!
