1. 5.2 Ways to Prove that Quadrilaterals are Parallelograms
Geometry
5.2 Ways to Prove that Quadrilaterals are Parallelograms

2. There are 5 Ways to Prove that a Quadrilateral is a
THE FIRST WAY. We already know the first one, by the defn. of that…
1) Both pairs of opp. sides // or
Defn. of
Parallelogram

3. THE SECOND WAY (Theorem)~
2) Both pairs of opp. sides =
Parallelogram

4. THE THIRD WAY (Theorem)~
3) One pair of opp. sides both // and =
Parallelogram

5. THE FOURTH WAY (Theorem)~
4) Both pairs of opp. ‘s = 7
Parallelogram

6. THE FIFTH WAY (Theorem)
5) Diagonals bisect each other
Parallelogram

7. The Five Ways to Show a Quadrilateral is a Parallelogram
1) Defn. of ~
2) Both pairs of opp. sides = ~
3) One pair of opp. sides both // and = ~
4) Both pairs of opp. ‘s = 7
5) Diagonals bisect each other

8. PG 173 CE 1. 2. 3. 4. 5. 6. 7. 8. 9.
10.
11.
12.

9. 7y
3x
4y + 21
45
(2x – 5)
3y
123
3y – 8 x2
y + 12
2x + 15

10. REVIEW: Angle Bisector Theorem for problem #151. 2. 3. 4. 5.
Given:
Prove: W M X N Z Y
REVIEW: Angle Bisector Theorem for problem #15

11. HW
P. 174 (1-10, 14, 19-22)
P. 384 (17)
Canned foods

12. One from the HW
P. 174 #6 Has two possible answers