Lesson 6.2
Thereom 6-1
Opposite sides of a parallelogram are congruent
m<Q + m<P=180
120 + m<S=180
m<S=60
Thereom 6-2
Opposite angles of a parallelogram are congruent
(Top left=B, Bottom left=A, Top right=D, Bottom right=C)
4m + 2 = 3m + 8
-3m -3m
m+2=8
-2 -2
m=6
BD= 4 x 6 - 15= 9
AC = BD, so AC=9
Thereom 6-3
The diagonals of a parallelogram bisect each other
Thereom 6-4
If three (or more) parallel lines cut off congruent segments on one transversal, then they cut off congruent segments on every transversal.