Set up the proportion as follows: [tex]\frac{bush (height)}{bush (length)} = \frac{building (height)}{building (length)}[/tex], then cross multiply to solve.
[tex]\frac{4}{6} = \frac{x}{24}[/tex]
4(24) = 6(x)
4(4) = x (divided both sides by 6)
16 = x
Answer: 16 ft