Question

5. A monument casts a 78 ft. shadow at the same time that a vertical yardstick casts a 4.5 ft. shadow. How high is the monument?​

Answer 1

Hello,

Using Thalès 's theorem:

Let's h the height of the monument.

`(1)/(h) =(4.5)/(78) \\\\h=(78)/(4.5) =(156)/(9) \approx{17.3\ (ft)}`

If you don't know what is the Thalès's theorem,

imagine that the similar triangles.