Polygons and Special Quadrilaterals (4/14/05)

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Polygons and Special Quadrilaterals (4/14/05)

• Check homework on board
• Ask homework questions
• Presentation
• Game Time
• Homework is worksheet

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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

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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)

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Special Quadrilaterals, cont

• 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)

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Special Quadrilaterals, cont

• 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!

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Special Quadrilaterals, cont

• 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!

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Helpful Tree Diagram
Quadrilateral Non-Special Parallelogram Trapezo
id 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.
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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.

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Game Time

• 5. What name(s) can be assigned to this?
• 6. What name(s) can be assigned to this?

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Game Time

• 7. What name(s) can be assigned to this?