how long is the shadow

Question

If a 5-foot-tall person casts an 8-foot shadow, how long is the shadow of a 12-foot-tall road sign? Use a proportion to set up and solve an equation. Round your answer to the nearest tenth of a foot if necessary.

Answer 1

Let x be the length of the shadow of 12 foot tall road sign

Using proportion of sides of the two triangles.

(5/12) = (8/x)

x = (12)(8)/(5)

   =96/5

   =19.2 ft