Question

Two nearby buildings are perpendicular to the ground, which is flat. One of the buildings is 30 feet tall and has a shadow that is 10 feet long. At the same time, the shadow of the other building is 3 feet long. How tall, in feet, is the other building? A. 6 B. 7 C. 8 D. 9

Answer 1

The sun's rays make the same angle, so the buildings and their shadows form similar triangles. Thus height/shadow = constant:
h2 = 30 * (3/10) = 9.
Answer: D.