Polygons and Special
Quadrilaterals (4/14/05)
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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?