So if you're adding two negatives you move left, positive you move right, and when you have to determine a negative, and a positive you just have to see which one is the farthest from zero which the farthest one's sign is either positive, or negative. Positive to move right, and negative to move left.
So the zip line forms a right triangle. The height of the triangle is 150 ft, and the opposite angle is 40°. The horizontal distance covered by the zip liner can be found with trigonometry, specifically with tangent.
tan 40° = 150 / x
x = 150 / tan 40°
x ≈ 179 feet
But this includes the 40 ft long body of water, so the amount of ground covered is:
