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Introduction to Section 6-2 “Parallelograms”

Definition

“A parallelogram is a quadrilateral that has both pairs of

opposite sides parallel to each other.”

Key Properties

1) Opposite sides are parallel

2) Opposite sides are congruent

3) Opposite angles are congruent

4) Diagonals bisect each other

5) Adjacent angles are supplementary

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Example #1

Given that m<A = 115° find the measures of the other

angles.

D C

BA

Example #2

Given the above figure, with m<B = 7x - 1 and

m<C = 8x + 16, find the measures of all four angles.

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Example #3

If AE = 2x + 6 and EC = 3x - 2, find AC.

E

D C

BA

Example#4

In the parallelogram depicted below, find all of the

missing interior angles.

74

48

42

E

D C

BA

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Example #5

Given that AB = 5x-8, CD = 3x +10,

BC = 7y+4 and DA = 10y-5, find the perimeter of ABCD.

D C

BA

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