Question

In the early afternoon a tree cast a shadow 2 ft. long & a 4.2 ft. tall boy next to the tree cast a shadow 0.7 ft. long, how tall is the tree?

Answer 1

\[\frac{ 0.7}{ x }=\frac{ 2 }{ 4.2 } \]

Answer 2

This is a proportion problem. Tree is to 2 ft as 4.2 ft boy is to .7 or in a math language:
x:2 :: 4.2:.7 The two values on extreme left and right are know as the "extremes" The two values in the middle are know as the "means" The rule is the product of the means equals the product of the extremes. Letting the tree be x

x:2 :: 4.2:.7
.7x = 8.4
x = 8.4/.7
x = 12

Answer 3

The tree is 12 ft tall.

Answer 4

Do you have any questions on the method used to solve this?