Answer:

Explanation:
![\displaystyle [5f + 83]° = [4f + 80]° \hookrightarrow (3)/(-1) = (-f)/(-1) \\ \\ -3 = f \\ \\ \\ [4[-3] + 80]°; [-12 + 80]° \\ \\ 68° = m\angle{FTH}](https://img.qammunity.org/2021/formulas/mathematics/high-school/fsa9zjl659sfni9qwcibcznnj7z01x7hjs.png)
As you can see, we plugged the m-value into the expression for angle 
 because if you recall, you can tell that angles
because if you recall, you can tell that angles 
 are vertical angles, and accourding to the Vertical Angles Theorem, these angles are considered congruent, therefore sixty-eight degrees is also the measure of angle
are vertical angles, and accourding to the Vertical Angles Theorem, these angles are considered congruent, therefore sixty-eight degrees is also the measure of angle 

I am joyous to assist you at any time.