Equations and inequalities

Question

A person 6 feet tall is standing at the base of a lamppost that is 25 feet tall and then begins to walk away from the lamppost. When the person is 10 feet from the lamppost, what is the length of the person's shadow? Round to the nearest tenth of a foot.

Answer 1

Using similar triangles of height to length of 6:x and 25:(x+10)

comparing the heights: 6:25

comparing the base of the triangles: x:(x+10)

6/25 = x/(x+10)

25x = 6(x+10) = 6x + 60

19x = 60

x = 3.16 feet length of the shadow