Download Section 8.2 Parallelograms

Geometry – Chapter 8 Lesson Plans
Section 8.2 –Parallelograms
Enduring Understandings: The student shall be able to:
1. identify and use the properties of parallelograms.
Standards:
19. Congruence
States and applies properties of triangles and quadrilaterals such as parallelograms,
rectangles, rhombi, squares, and trapezoids.
21. Similarity
Uses properties of quadrilaterals to establish and test relationships involving
diagonals, angles, and lines of symmetry.
Essential Questions: What is a parallelogram? What properties do they have?
Warm up/Opener:
Activities: Lesson/Body:
A parallelogram is a quadrilateral wit two pairs of parallel sides. Draw a picture and
designate the parallel sides with arrows.
Thm. 8-2: Opposite angles of a parallelogram are congruent.
Prove this by alternate interior angles and then corresponding angles are congruent.
Thm. 8-3: Opposite sides of a parallelogram are congruent.
Prove this by drawing a diagonal and showing the two triangles are congruent by ASA
and then the sides are congruent by CPCTC.
Thm. 8-4: The consecutive angles of a parallelogram are supplementary.
Prove this by alternate interior angles are congruent, supplementary angles.
Thm 8-5: The diagonals of a parallelogram bisect each other.
Prove this by alt int angles are congruent, small triangles congruent by ASA and
diagonals pieces congruent by CPCTC, and bisecting by definition of bisectors.
Thm 8-6: A diagonal of a parallelogram separates it into two congruent triangles.
Prove by above
Assessments: CW WS 8.2
HW pg 320 – 321, # 11-33 odd (12)