What is the slope of (1 -19) and (-2 -7)

David must install fencing around a lot that is shaped like a right angle. the side of lot that runs east-west is 200 ft long. the side of the lot runs north-south is 125 ft long. calculate how many feet of fencing he will need to surround the entire lot.

Identify an equation in point slope form for the line perpendicular to y=3x+5 that passes through (4,-1)

Having a hard time understanding this question (see attachment).