Question

Bob is trying to see if his shadow is longer than Kevin’s. Kevin is 3 feet tall, and Bob is 2½ feet tall. Kevin’s shadow is 5 feet long. Help Bob find the length of his shadow

Answer 1

Given parameters:

Height of Kevin  = 3ft

Height of Bob = 2.5ft

Hieght of Kevin's shadow = 5ft

Unknown:

Length of Bob's shadow = ?

We can simply set up simple ratio to solve this problem.

 The ratio of Kevin's height to Bob's height is 3 : 2.5

  The ratio of their shadow should also be 5: Bob's shadow height

Equating the two of them should give a fairly constant ratio;

         $\frac{3}{2.5} = \frac{5}{Bob}$  

            3Bob  = 5 x 2.5

 Bob's shadow height  = $\frac{5 x 2.5}{3}$   = 4.2ft

The height of Bob's shadow is  4.2ft.