Question

Jill is planting a tree. She needs to dig a hole that is 2 feet deep for every 5 feet of tree height.
How deep should she dig the hole if her tree is 18 feet tall?


? = 9 feet

? = 7.2 feet

? = 8.1 feet

? = 7.8 feet

Answer 1

To determine how deep Jill should dig the hole for her tree, we can use the ratio provided: 2 feet deep for every 5 feet of tree height.

First, we need to set up the proportion. If we let \( h \) be the hole depth for an 18-foot tall tree, we can set up the following relationship based on the ratio:

\[
\frac{h}{2} = \frac{18}{5}
\]

Now we can cross-multiply to solve for \( h \):

\[
5h = 2 \times 18
\]

Calculating the right side gives:

\[
5h = 36
\]

Now, divide both sides by 5 to solve for \( h \):

\[
h = \frac{36}{5} = 7.2 \text{ feet}
\]

Therefore, Jill should dig the hole **7.2 feet** deep.

So the answer is:

**? = 7.2 feet**