To get the perimeter of the quadrilateral, the distance formula can be used. We simply have to subtract the y coordinate of one point to another and the same for the x coordinate. The square root of the sum of the squares of the difference is the distance.The results can then be added to get the perimeter. So, CF = sqrt ( (2-(-1))^2 + (-1-(-2))^2 ) = sqrt(10) FE = sqrt ( (-2-1)^2 + (2-1)^2 ) = sqrt(10) ED = sqrt ( (-1-(-2))^2 + (-2-2)^2 ) = sqrt(17) DC = sqrt ( (2-(-1)^2 + (-1-(-2))^2 ) = sqrt(10)
P = CF + FE + ED + DC = sqrt(10) + sqrt(10) + sqrt(17) + sqrt(10) = 13.61