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Today…. Go over homework from 5-1 Do practice worksheet for 5-1 (collected and graded) Notes for 5-2 Assign Homework. Here we go!!. Let’s put the answers on the board!! Let’s do the worksheet!. Section 5.2 Ways to Prove that Quadrilaterals Are Parallelograms.
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Today…. • Go over homework from 5-1 • Do practice worksheet for 5-1 (collected and graded) • Notes for 5-2 • Assign Homework
Here we go!! • Let’s put the answers on the board!! • Let’s do the worksheet!
Section 5.2Ways to Prove that Quadrilaterals Are Parallelograms Let’s go backwards with the 5 ways to prove a quadrilateral is a parallelogram!!!
Recap (quietly write down your answers): • What is a quadrilateral? • (a 4-sided figure) • What is a parallelogram? • (both pairs of opposite sides parallel) • Is every quadrilateral a parallelogram? • no • Is every parallelogram a quadrilateral? • yes
Objective Prove a Quadrilateral is a Parallelogram!
Opposite sides of a parallelogram are__________. CONGRUENT!! Yesterday…(don’t write)
If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram. If AB CD and BC DA, then ABCD is a ||-ogram. Converse (don’t write): C B D A
Opposite angles of a parallelogram are __________ CONGRUENT!! Yesterday…(don’t write)
If both pairs of opposite angles of a quadrilateral are congruent, then the quadrilateral is a parallelogram. If <A <C and <B <D, then ABCD is a ||-ogram. Converse (don’t write): B C D A
Diagonals of a parallelogram ________ each other. BISECT!! Yesterday…(don’t write)
If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a parallelogram. If AB DC and BC AD, then ABCD is a ||-ogram. Converse (don’t write): B C D A
If one pair of opposite sides are parallel and congruent, then the quadrilateral is a parallelogram. If BC AD and BC || AD, then ABCD is a ||-ogram. Theorem 5-5 (write!!!): B C D A
The Big 5!! (write)! • Def of parallelogram:Both pairs of opposite sides are parallel. • Theorem 5-4: Both pairs of opposite sides are congruent. • Theorem 5-5:One pair of opposite sides are both congruent and parallel. • Theorem 5-6: Both pairs of opposite angles are congruent. • Theorem 5-7:Diagonals bisect each other.
Go to page 173 and do 1-9. Write yes or no, and the theorem or definition that proves it so. That rhymed. • yes, thm 5-4 • Yes, thm 5-5 • No • Yes, thm 5-7 • No • Yes, either def. of //gram, or thm 5-6 • Yes, def of //gram • No • Yes, either def. of //gram, or thm 5-6
Closure! Name the definition or theorem on little piece of paper! • BE = ED, CE = EA • m<BAD = m<DCB, m<ADC = m<CBA • BC || AD, AB || DC • 4. BC || AD, BC = AD C B E D A
Homework! • Worksheet • Page 174 1-5 • Page 175 19-22