Answer: 25 feet tall
Explanation:
First, let's take a look at the person. If they are 5 feet tall and cast a shadow of 3 feet, we can easily convert this into a proportion: 5 feet tall: 3 feet shadow.
Continuing with this method, we can convert the tree into a proportion: x feet tall: 15 feet shadow.
So, 5:3=x:15. Mathematically, think of it as 5/3=x/15.
To find x, you will need to multiply 15 to both sides, or perform cross multiplication. (5/3)(15)=(x/15)(15). This will equal 25. The tree is 25 feet tall.