
David W. answered 04/08/16
Tutor
4.7
(90)
Experienced Prof
Many, many book problems, homework problems, and test problems have "Pythagorean Triples" of:
n*1 n*1 n*√2
n*1 n*√3 n*2
n*3 n*4 n*5
...
Also, the angles of each of these triangles are well-known. So, learning them will save you a lot of time.
The ground leg is 4*3; the height of the building is 4*4; so the hypotenuse (the ladder) must be 4*5=20.
Calculate that using the Pythagorean Theorem once, then use that information to check your answer, then to solve problems very quickly.