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Polygons and Special Quadrilaterals (4/14/05) • • • • • Check homework on board Ask homework questions Presentation “Game Time” Homework is worksheet Does the figure have 4 sides? • Four sides = decide which special quadrilateral it is. • Not four sides = triangle, pentagon, hexagon (or other, we will focus on these 3) • 3 sides = triangle • 5 sides = pentagon • 6 sides = hexagon Special Quadrilaterals • Does the figure have both pairs of opposite sides parallel? • No! (Like this) • Are just a pair of opposite sides parallel? • Yes! Well then it could be a trapezoid (a quadrilateral having only one pair of opposite sides parallel) (Like this) Special Quadrilaterals, con’t • Does the figure have both pairs of opposite sides parallel? • Yes! Well then if both pairs of opposite sides are equal then it could be a parallelogram (a quadrilateral with opposite sides parallel and equal) (Like these) Special Quadrilaterals, con’t • Are all four sides equal? • If yes, then it could be a rhombus (a parallelogram with four equal sides and sometimes one with no right angles) • If all four sides are equal and all the angles are right angles then it is a square! Special Quadrilaterals, con’t • If all the angles are right angles, but all the sides are not equal it could be a rectangle (a parallelogram all of whose angles are right angles; [especially : one with adjacent sides of unequal length]) (Like this) • NOTE: More than two names can apply to one figure! Helpful Tree Diagram Quadrilateral “Non-Special” Parallelogram Trapezoid Parallelogram Rhombus Rectangle Square NOTE: This chart is designed to help you see the relationships, it is still up to you to decide which name(s) apply to a shape. Game Time • With your partner answer the following five questions: • 1. Is every rhombus a square? Why or why not? • 2. Is every rectangle a square? Why or why not? • 3. Sketch an example of a trapezoid. • 4. Sketch a rhombus that is not a square. Game Time • 5. What name(s) can be assigned to this? • 6. What name(s) can be assigned to this? Game Time • 7. What name(s) can be assigned to this?