Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: 9 . on level farmland , two runners leave at the same time from the intersection of two country roads . one runner jogs due north at a constant rate of 6 miles per hour while the second runner jogs due east at a constant rate that is 2 miles per hour faster than the first runner ' s rate . how far apart , to the nearest mile , will they be after 1 / 2 hour ?
5
√(13)^2 + 6