Since 4pi/3 = 3pi/3 + pi/3 = pi + pi/3, that means it goes past the angle of pi (the negative x-axis), and an additional pi/3 radians. So this gives you a diagonal line that passes through the origin, from the third quadrant through to the first quadrant, and makes an angle of 60 degrees with the negative x-axis.
X + 60 = 100 (because they are vertical angles, which means that because they are directly opposite of each other, they are of the same measurements).
Solve for x. Isolate the x, subtract 60 from both sides
x + 60 = 100
x + 60 (-60) = 100 (-60)
x = 100 (-60)
x = 40
40° should be your answer
hope this helps
Answer: 
Step-by-step explanation:
Move all terms to one side.

Use the Quadratic Formula.
, 
13/1 because we can divide both sides by 5 and we’ll get 13/1