# 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.