2. How Can You Tell That All Four of These Figures Are Quadrilaterals? What do they all have in common?

3. Quadrilaterals are… Polygons Four sided and have four vertices The angles add up to 360 degrees They are classified by the different sizes of their sides and angles Here are two examples:

4. There are several types of quadrilaterals.

5. Square A square has equal sides and every angle is a right angle (90°) Also opposite sides are parallel. A square also fits the definition of a rectangle (all angles are 90°), and a rhombus (all sides are equal length).

6. Rectangle means "right angle" and means shows equal sides A rectangle is a four-sided shape where every angle is a right angle (90°). Also opposite sides are parallel and of equal length.

7. Rhombus A rhombus is a four-sided shape where all sides have equal length. Also opposite sides are parallel and opposite angles are equal.

8. Parallelogram a quadrilateral with both pairs of opposite sides parallel opposite sides as well as opposite angles are congruent.

9. Trapezoid A quadrilateral with one set of parallel sides A trapezoid is not a parallelogram because only one pair of sides is parallel.

10. By Definition… A square is - A polygon A quadrilateral A parallelogram A rhombus A rectangle

11. Can you guess the classifications for the following quadrilaterals? Check the next slide for answers.

12. Answers :

13. How else can these other polygons be classified? Rhombus? Trapezoid? Rectangle? Parallelogram?

14. Guess the missing degrees! 44°, 72°, 36°,____° Answer: 208° 90 °, 90 °, 90°, ____° Answer: 90° 120°, 55°, 55°, ____° Answer: 130° 80°, 120°, 66°, ____° Answer: 94°

15. Try manipulating some of the shapes by viewing this site. Remember to check the sum of the angles as you change the shape on the link below. It will always add up to 360°. Reshape the quadrilateral