Answer:
< 3 = 3x + 105°
Explanation:
There is remot angle theory which is the exterior angle is congrent to the other non adjecent angle in triangle.
so <1 + <EDF = <3
(3x + 15 ) ° + 90° = <3
3x°+ 105° = <3
< 3 = 3x + 105° .... so the measur of angle 3 interms of x is 3x + 105°