Find the perimeter od the ploygon defined by the coordinates (5,8), (-5,0), and (-1,8)

D = sqrt of (x2 -x1)^2 + (y2-y1)^2

1) sqrt of (-5-5)^2 + (0-8)^2 = sqrt of 100 + 64

2) sqrt of (-1-(-5))^2 + (8-0)^2 = sqrt of 16 + 64

3) sqrt of (-1-5)^2 + (8-8)^2 = sqrt of 36 + 0

P = sqrt 164 + sqrt 80 + 6

??? not sure