Answer:
m<5 = 129°
Step-by-step explanation:
m<5 + 51° = 180° => same-side interior angles theorem (same-side interior angles are supplementary)
m<5 + 51° - 51° = 180° - 51° => subtraction property of equality
solution given:
<5+<51°=180°[co- interior angle]
<5=180°-<51°=129°
<4=129° is your answer
