To find out whetherlinesare parallel,you can find the slopeby computing. If
the slopesare the same,the linesare parallel.Similarly, if you wantto find out if anglesare right angles,
you can test the slopesof their lines.Perpendicularlineswill haveslopesthat are oppositereciprocalsof
eachother.
Example 4
Classifythe shapeon the coordinategrid below.First identifywhetherthe sidesare congruent.You can use the distanceformulafour timesto find the distance
betweenthe vertices.
For segment , find the distancebetween(-1,3)and (1,9).For segment , find the distancebetween(1, 9) and (3, 3).For segment , find the distancebetween(3, 3) and (1, -3).