Topic 6 Quadrilaterals

Topic 6
Quadrilaterals

6-2 Parallelograms and Rectangles

A quadrilateral is a polygon (shape) that has 4 sides, 4 angles, and 4 vertices.

Quadrilaterals have specific names and properties which you will learn throughout this unit.

Quadrilaterals

Today we will focus on the properties of parallelograms and rectangles.

First, lets take a look at the properties of a parallelogram.

Multiple Choice

What do you notice about the opposite angles?

Angle A and Angle C?

• They are congruent (the same)

• They are supplementary (the sum equals 180)

• They are complementary (the sum equals 90)

Multiple Choice

What do you notice about the consecutive angles (side by side) of a parallelogram?

Angle D and Angle C?

• They are congruent (the same)

• They are supplementary (the sum equals 180)

• They are complementary (the sum equals 90)

Multiple Choice

What do you notice about the opposite sides?

SIDE AD and SIDE BC?

• They are congruent (the same)

• They are supplementary (the sum equals 180)

• They are complementary (the sum equals 90)

Multiple Choice

Complete the sentence:

The diagonals of a parallelogram __________ each other.

• Bisect (cut in half)

• are perpendicular to (they intersect and make a right angle)

• are congruent to (the same)

What you should have just learned is:

• Opposite angles are congruent.

• Consecutive angles are supplementary.

• Opposite sides are congruent.

• Diagonals bisect each other.

• Opposite sides are parallel.

Properties of a Parallelogram

Finally, lets look at the properties of a rectangle.

Multiple Choice

Look at the picture of rectangle ABCD.

What do you notice about the angles?

• All the angles are 90 degrees

• All the angles are 180 degrees

• All the angles are 45 degrees

Multiple Choice

Look at the picture of rectangle ABCD.

The diagonals are congruent

• TRUE

• FALSE

The properties of a rectangle are the same as the properties of a parallelogram, with these two added properties:

• All angles are right angles (equal 90 degrees) .

• Diagonals are congruent.

Properties of a Rectangle