3.5 ft child casts a 60-in. shadow. The child is next to a telephone pole that casts a 50-ft shadow, forming similar triangles. How tall is the telephone pole?

Question

I have a test tomorrow and these are some of the questions we have to do for study and I cannot figure it out.

Answer 1

Let's use measurements in feet.  60 inches = 5 feet.

 

Since these are similar triangles, we can use a proportion to solve for the height of the pole.

 

child's height/length of child's shadow

                 

                     = pole height/length of pole's shadow

 

3.5/5 = y/50

 

5y = 175 by cross-multiplication.

 

y = 35 ft

Answer 2

 

3.5 ft child   ---> 5 ft shadow

 

let x be height of telephone pole:

 

x ---> 50 ft. shadow

 

so,

 

3.5/5 = x/50

3.5*50/5 = x

 

x = 35 ft.