Show that the points (0,-1),(-2,3),(6,7) and (8,3) are vertices of a rectangle.

Explanation

`therefore absbar(AB) = sqrt((0 + 2)^2 + (-1-3)^2)`
`sqrt(4+6) = sqrt(20)`
`absbar(AB) = sqrt((-2-6)^2 + (3-7)^2)`
`sqrt(64+16) = sqrt(80)`
`absbar(CD) = sqrt((6-8)^2 + (7-3)^2)`
`sqrt(4+16) = sqrt(20)`
`absbar(AD) = sqrt((8-0)^2 + (3+1)^2)`
= `sqrt(64+16) = sqrt(80)`
`therefore` the opposite sides are equal and two consecutive sides are perpendicular So it is a rectangle.