1. Introduction to Quadrilaterals
Lesson 19
Introduction to Quadrilaterals

2. A quadrilateral is a polygon with four sides
Properties
Parallelogram
Both pairs of opposite sides are parallel
Kite
Exactly 2 pairs of consecutive sides are congruent
Trapezoid
Exactly one pair of sides are parallel
Trapezium
No parallel sides
Parallelogram
Properties
Rectangle
A parallelogram with 4 right angles
Rhombus
A parallelogram with 4 congruent sides
Square
A parallelogram with 4 right angles and 4 congruent sides

3. Quadrilateral Family Tree
This will help to determine types of quadrilaterals and help with the sometime, always, never questions Can a kite be a rhombus? Never Can a rectangle be a square? Sometimes

4. Classify quadrilateral ABCD & explain
Trapezoid Exactly one pair of parallel sides Is it isosceles? Why or why not? No, 𝐴𝐵 and 𝐶𝐷 are not congruent

5. Classify quadrilateral WXYZ & explain
Rectangle Because of the 4 right angles, you can show opposite sides are parallel since same side interior angles are supplementary Is it a square? Why or why not? No all four sides are not congruent

6. No diamonds in Geometry!
What kind of a quadrilateral is the infield of a baseball diamond?
square
What other classification of quadrilaterals is it?
rectangle, rhombus, parallelogram

7. How far does the batter run after she hits a homerun in softball?
What is the base length in softball? 60 ft What is the formula for the perimeter of a square? 𝑃=4𝑠 𝑃=4 60 𝑃=240 𝑓𝑡

8. Questions/Reviews
Future lessons we will learn more about these shapes like:
Angles
Sides
Diagonals
Area & Perimeter