A rope goes from one building to another. The distance between the buildings is 12m, and the rope is tied at each building at a point 8m and 3m from the ground. Find the length of the rope.

The 8m point is 5m above the other point. So we have a right triangle with base 12m and height 5m so the hypotenuse is the length of the rope and from Pythagoras we have the length=√12²+5²=√169=13m.