Answer
A) 32 ft
Work Step by Step
This is a proportion problem. You already know that a 6-feet tall object creates a 9-feet tall shadow. The variable is the height of a tree with a 48 ft shadow. You would use the equation shown below:
$\frac{6}{9}=\frac{x}{48}$
Then, cross multiply and solve.
$6\times48=x\times9$
$9x=288$
$(9x)\div9=(288)\div9$
$x=32$
The tree is 32 ft tall.