Trey is running in a race. He has completed 1/4 of the race so far. He has already run 1.2 miles. How many more miles must Trey run to complete the race?

To find out how many more miles Trey must run to complete the race, we first need to determine the total distance of the race.

Since Trey has completed \( \frac{1}{4} \) of the race and has run 1.2 miles, we can set up the equation for the total distance \( D \) of the race:

\[
\frac{1}{4} D = 1.2 \text{ miles}
\]

To find \( D \), we multiply both sides of the equation by 4:

\[
D = 1.2 \times 4
\]
\[
D = 4.8 \text{ miles}
\]

Now that we know the total distance of the race is 4.8 miles, we can calculate how much more Trey must run. Since he has already completed 1.2 miles, we subtract that from the total distance:

\[
\text{Miles left} = D - \text{miles already run} = 4.8 - 1.2
\]
\[
\text{Miles left} = 3.6 \text{ miles}
\]

Therefore, Trey must run **3.6 miles** more to complete the race.

The correct answer is **3.6 miles**.