The length is 19.5 feet. this is because when you add the yards, it equals 15 feet. Next, add 1 + 2 feet from the first and second jump. 10+8 inches equal 1.5 feet. Next, add 15 feet+3 feet+1.5 feet to get 19.5 feet.
What you do, to convert a percention to a fraction is to divide the percent by 100. This will give you the fraction of that percent. Knowing this, you can eliminate all the other possible answers that have been listed.
Points: (0,4) and (2,-3)
Find slope: (-3-4)/(2) = -7/2
4 = -7/2(0) + b, b = 4
Equation: y = -7/2x + 4