If you're solving for the length of that side just use the pythagorean theorem so the hypotenuse or your missing side equals:
hypotenuse = square root ( 5.5^2 + 4.83^3 )
hypotenuse = square root (30.25 + 23.3289)
hypotenuse = square root (53.5789)
hypotenuse = 7.32
So, the total distance is 7.32 miles.