Can someone explain what you do here

a:

b:

the answer choices all have the same value for b, so I dont have to solve for b at all.

c:

d:

d is inside a 45-45-90 triangle. Therefore, side a and d must be of the same length.

the graph line crosses the x axis at both -6 and -2, so the answer would be the second one.

3 ft is your answer