72º
Explanation:
The total degrees of a line is 180.
So, both angles add up to 180.
180 = 5x+8 + 3x+12
Solve for x.
Combine like terms
180 = 5x+8+3x+12
180= 8x +20
Subtract 20 from both sides
180 -20= 8x +20 -20
160=8x
Divide both sides by 8
160 /8 = 8x /8
20=x
Now that we x, we can plug that into the smaller angle (the one on the right) to find your answer.
3(20) + 12
60 + 12
72
And there you have it! Your answer is 72º.
Hope this helps!
Let me know if you need anything else :)