Question 863133
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Hi
(1,1), 
(-1,5)  D = {{{sqrt ((x[1]-x[2])^2+(y[1]-y[2])^2))}}} 
(1,7)   D = {{{sqrt ((x[1]-x[2])^2+(y[1]-y[2])^2))}}}
(1,1)   D = {{{sqrt ((x[1]-x[2])^2+(y[1]-y[2])^2))}}} = {{{sqrt(0+36)}}} = 6
Find Ds in each case(did one for You, and add them to find Perimeter