Question

A boy stands 1 meter away from a lamppost. He is 1.8 meters tall and casts a shadow 2 meters long in the light from the lamp. How tall is the lamppost?

Answer 1

set up a proportion using 2 similar right triangles

smaller triangle has side ratio ---> 1.8:2
larger triangle has side ratio ---> x:3

\[\frac{x}{3} = \frac{1.8}{2}\]