Thomas decides to use the method of proportions and similar
triangles to find the height of a lamppost. He measures the length of
the post's shadow and finds it is 5 feet long. Then, he holds a 1-foot
ruler perpendicular to the ground and finds that it casts a 2-inch
shadow. How tall is the lamppost?
a. 2.5 ft c. 30 ft
b. 12 ft d. 60 ft