1407 LG: Lesson 6'7: Areas of Triangles and Quadrilaterals

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1/4/07 LG Lesson 6.7 Areas of
Triangles and Quadrilaterals

• Warm-Up Find perimeter (P) or Area (A)
• 1. P 2L 2W, L3 and W5
• 2. A?r2 ?3.14 and r 3 ft
• 3. Find P and A base 8cm
  height2.5 cm
• 4. Name the shapes, then Explain what they have
  in common.

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Warm-up Solutions

• 1. P 2L 2W, L3 and W5 P2(3) 2(5)16
• 2. A?r2 A3.14(3 ft)2 A3.14(9ft2)28.3 ft2
  
• 3. P2(8)2(2.5) 21cm base 8cm
  A B x H8cm x 2.5cm 20cm2 height2.5cm
• 4. Name the shapes, then Explain what they have
  in common.

Rhombus and Kite diagonals form 90 angle or
- Rectangle and Isosceles Trapezoid diagonals
are congruent
Kite
Isosceles Trapezoid
Rectangle
Rhombus
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HW 6.5 Solutions

• 3.
• 4. Kite
• 5.
• 7. (713)/2 9
• (73)/2 5
• bases
• consecutive sides
• or adjacent sides

• 13.
• 14. Opposite Ls
• 15.
• 16. KL136, M44
• 17.
• 18. J82, KL98
• 19. Ave. Bases
• 20. (1416)/2 15
• 21.

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HW Solutions

• (x9) / 2 7
• (x9) 72
• x9 14
• -9 -9
• x 5
• Use Pythag. Theorem
• 28.

• 29. 31.
• 32. Opposite angles H, F are congruent
• 90 90 110 G 360
• 290 G 360, mLG70
• 36. Yes. Kite.
• ABADv53
• CBCD v265
• 2 pairs of consecutive congruent sides.
• Opposite sides not congruent

3.6
5
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Area of Triangle

• A BxH/2 (half a square, so
  ________)
• Height makes a 90 w/ the base
• Area of Parallelogram
• A B x H Same for rectangle, squares
• Bases are parallel
  sides______

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Area of Quadrilaterals

• Trapezoid A Ave.Bases x H
• A midsegment x H
• A ½ (b1b2) x H
• Kite A ½ (diagonals multiplied)
• A ½ (d1 d2)
• Rhombus A ½ (diagonals multiplied)
• A ½ (d1 d2)
• Equations for ______ _________ are _______

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HW 6.7

• p. 376
• 3-11, 14-21, 26-28
• 35-37, 45-47, 63-65
• FYI DUE FRIDAY (ch 4 6)
• - Absent work
• - Make-up quizzes/tests