Daniel decides to use the method of proportions and similar
triangles to find the height of a tower. He measures the length of the
tower's shadow and finds it is 72 feet long. Then he holds a 12-inch
ruler perpendicular to the ground and finds that it casts an 24-inch
shadow. How tall is the tower?
a. 3 ft c. 36 ft
b. 4 ft d. 144 ft