Because the route forms an isosceles right triangle, two legs of the triangle are equal.
There will be two angles, equal to 45°, and a 90° angle as shown in the figure below.
The distance from Old Mill is the same as the distance from Clarksville to Hamilton, equal to 48 miles.
Let x = distance between Old Mill and Hamilton.
By definition,
cos 45° = 48/x
or
x = 48/cos 45° = 67.882 mi
Answer: 68 miles (nearest mile)
