If my calculations are correct, the percentage decrease faced here is roughly 38.2%. Based on the calculations, the bicycle costs 199$ and when the cost is subtracted from 520, you would create the percentage of 38.2%.
17 / 6
2 5/6.
2 whole number 5/6.
Assuming these are the angles for the inside of the triangle:
c=2
Step-by-step:
108+42+15c=180
150+15c=180
15c=30
c=2