35 feet tall
Work Step by Step
The problem states that the two triangles are similar triangles. This means that all of the sides are proportional. We will call x the side that we want to find (the height of the pole). We need to put lengths in the same units, so we divide 60 inches by 12 to get that the child's shadow is 5 feet long. Thus, we set up the equation: x/3.5=50/5. We multiply both sides of the equation by 3.5 to isolate x and to obtain that x=35. Thus, the phone pole is 35 feet tall.