Answer :
Find the distances between every pair of vertices using the distance formula:
d = √[(x2 - x1)^2 + (y2 - y1)^2]
1) d = √[(5+4)^2 + (2+1)^2] = √[81 + 9] = √90
2) d = √[(1)^2 + 4^2] = √[1 + 16] = √17
3) d = √[8^2 + 1^2] = √[64 + 1] = √65
Perimeter = √90 + √17 + √65 = 21.7
d = √[(x2 - x1)^2 + (y2 - y1)^2]
1) d = √[(5+4)^2 + (2+1)^2] = √[81 + 9] = √90
2) d = √[(1)^2 + 4^2] = √[1 + 16] = √17
3) d = √[8^2 + 1^2] = √[64 + 1] = √65
Perimeter = √90 + √17 + √65 = 21.7
