One way to determine the slope of a line is from two points on a line.
We can use the ones already indicated on the graph, (0,4) and (3,5).
The slope is change in y divided by change in x,

Answer: 1/3
Let's set the measure of each angle equal to 540 degrees.
4x + 4x + 5x + 2 + 96 + 5x - 8 = 540
Combine like terms.
18x + 90 = 540
Subtract 90 from both sides.
18x = 450
Divide both sides by 18
x = 25
Change 25% to .25. Multiply .25 by 50 to get 12.5. Subtract 12.5 from 50 to get $37.50