Answer:
x = 18
Step-by-step explanation:
All triangle angles add up to 180 so:
x + 5x + 72 = 180
6x + 72 = 180
6x = 180 - 72
6x = 108
21.6
5x+72=180 (set it to 180 because the total angle sum of a triangle is 180)
5x=108
x=21.6
