perpendicular bisector of a segment- a line perpendicular to a segment at the segment's midpointTheorem 3-4-1- If two intersecting lines from a linear pair of congruent angles, then the lines are perpendicularTheorem 3-4-2- In a plane, if a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other lineTheorem 3-4-3- If two coplanar lines are perpendicular to the same line, then the two lines are parallel to each otherrise- y2-y1run- x2-x1parallel- the lines have the same slopeperpendicular- the product of the slopes is -1parallel lines- same slope different
- y-interceptintersecting lines- different slopescoinciding lines- same slope same
- y-interceptpoint slope formy-y1=m(x-x1)slope-intercept formy=mx+bequation of a vertical line- x
- undefinedequation of a horizontal line- y
- zeroacute triangle- 3 acute anglesequlangular- 3 congruent acute anglesright triangle- one right triangleobtuse triangle- one obtuse triangleequilateral triangle- three congruent sidesisosocles triangle- at least two congruent sidesscalene triangle- no congruent sidesmidpoint formula- x1+x2 / 2, y1+y2/2