Amelia casts a shadow 5 feet long. Her father, who is 6 feet tall, casts a shadow 8 feet long. How tall is Amelia?

Using the ratio height/shadow, the proportion x feet/5 feet =6 feet/8 feet can be used to find the unknown height. Cross multiply. 8x = 5 × 6, so 8x = 30 and x = 30/8 =3(3/4) feet. Convert 3/4 feet to inches. 3/4 * 12 = 9 inches. The height is therefore 3 feet 9 inches.