You start driving north for 24 miles, turn right, and drive east for another 70 miles. how many miles must you travel to return directly back to your starting point?

If you drive directly north, you are following a path that looks like a perfectly vertical line.  Turning to drive directly east has you on a perfectly horizontal path.  To connect where you are after that to where you started, you will construct what happens to be the hypotenuse of a right triangle.  We can solve for this length (we will call it "c") by using Pythagorean's Theorem.    and  .  Add to get that    and  c = 74.  There you go!