parallelograms

eww

PBT

if a point is on the perpendicular bisector of a segment, then the point is equidistant to the endpoints of the segment

ABT

if a point is on the bisector of an angle, then the point is equidistant to the sides of the angle

theorem 1

if two lines are parallel, then all points on one line are equidistant from the other line

theorem 2

if three parallel lines cut off congruent segments on one transversal, then they cut off congruent segments on every transversal

theorem 3

a line that contains the midpoint of one side of a triangle and is parallel to another side passes through the midpoint of the third side

theorem 4

the segment that joins the midpoints of two sides of a triangle (1) is parallel to the third side and (2) half as long as the third side

how to prove quadrilateral is a parallelogram

opposite sides congruent, opposite sides parallel, diagonals bisect each other, one pair of opposite sides is both congruent and parallel