Trapezoids and Isosceles Trapezoids

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Trapezoids and Isosceles Trapezoids
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Review

• Using P for Parallelogram, R for rectangle, S for
  square and Rh for Rhombus, write the letters of
  all the quadrilaterals that have these
  properties.
• Perpendicular diagonals
• Diagonals that bisect each other
• Congruent diagonals
• Two pairs of congruent opposite angles
• Supplementary consecutive angles
• Diagonals that bisect opposite angles
• Four right angles
• Two pairs of opposite parallel sides

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Trapezoid

• A Quadrilateral with exactly one pair of parallel
  sides.

Base
Leg
Leg
Base
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Median

• The segment that joins the midpoints of the
  trapezoids legs

Median
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Median Continued

• The median is parallel to the base and its
  measure is one-half the sum of the measures of
  the bases.
• The formula that relates the bases to the median
  is ½ (base 1 base 2)

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Example 1
If DF 32, EF ? If AF 22 and CD 18, find
BE If the measure of angle F 82, find angle
DEB If CD 2x-3, AF 4x 7 and BE 11, find
the value of x If CA DF and angle A 52 find
angle C, angle D, angle F and the measure of
angle CBE
C
D
B
E
F
A
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Isosceles Trapezoid

• A trapezoid with congruent legs.

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Properties of Isosceles Trapezoids (additional to
Trapeszoids)

• Both pairs of base angle are congruent
• The diagonals are congruent

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Example 2
Find the value of x in the following isosceles
trapezoid
G
H
3x-1
L
K
10
J
I
7x 1
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Practice

• Practice
• Practice