So I have a problem. The problem says: A fence 8 ft tall rubs parallel to a tall building at a distance of 4 ft from the building. What is the length of the shortest ladder that will reach from the ground over the fence to the wall of the building? I drew a picture to help, but I can't draw it on here. I drew a right triangle, it's fairly large. Halfway through the base, there's a straight line up representing the fence. I then made the hypotenuse of the entire triangle L. The wall is h. 1.I then set up a proportion. It's (x/8)=((x+4)/(h)) 2.I solved the proportion for x and got 32/(h-8) 3.I then said (x+4)^2+h^2=L^2 I plugged in the x value i solved the proportion for into the above equation and got (((4h)/(h-8))^2)+(h^2)^(1/2))=L (It might help to right this out instead of looking at it. Now I have to take the derivative of this and set it equal to zero.. But I keep messing it up.. Can somebody show me how to do it? I have been working and realized I can take the derivative of the Pythagorean theorem mentioned in step 3. But I still have trouble solving this. can somebody please help?