A steel pipe is being carried horizontally down a hallway that is 9ft wide. At the end of the hallway there is a right turn into a hallway that is 6ft wide. What is the length of the longest pipe that can be carried horizontally around the corner? (Hint: minimize the line) I have looked at this problem and tried many ways to solve it. I cannot think of a way to relate my information to make a derivable function. I did make a bunch of triangles and using geometry I'm pretty sure the answer is 21ft but man if I can't do this with calculus. Help!