You start driving north for 15 miles, turn right, and drive east for another 8 miles. At the end of driving, what is your straight line distance from your starting point?
So we have a triangle with legs 15 and 8.
using the pythog. thereom we have
152 + 82 = c2
So
c^2 = 289
c = sqrt(289)
If you don't understand anything feel free to ask!