Jon S. answered 08/21/20
Patient and Knowledgeable Math and English Tutor
Use distance formula to calculate lengths of segments between 4 points:
Distance formula = sqrt( (x2-x1)^2 + (y2-y1)^2), where (x1,y1) and (x2,y2) are two consecutive points.
Apply distance formula for (x1,y1) and (x2,y2) = L(1,4) and M(4,0) --> distance is 5
Apply distance formula for (x1,y1) and (x2,y2) = M(4,0) and N(2,0) ---> distance is 2
Apply distance formula for (x1,y1) and (x2,y2) = N(2,0) and P(-1,-2) ---> distance is 3.61
Apply distance formula for (x1,y1) and (x2,y2) = P(-1,-2) and L(1,4) ---> distance is 6.32
Add up all 4 distances to get perimeter = 16.93