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6.6 Trapezoids and Kites. Last set of quadrilateral properties. Terminology:. Terminology:. Terminology:. Terminology:. Start with the trapezoid. Start with the trapezoid. Start with the trapezoid. Parallel sides are called bases. Start with the trapezoid.
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6.6 Trapezoids and Kites Last set of quadrilateral properties
Start with the trapezoid • Parallel sides are called bases
Start with the trapezoid • Non parallel sides are called legs.
Start with the trapezoid • Since one pair is parallel
Start with the trapezoid • Since one pair is parallel Angles on the same leg are supplementary.
Now for the special • Isosceles trapezoid is a trapezoid whose legs are congruent.
And now for the proof, drawing in perpendiculars A B C D E F
Why is ? A B C D E F
Remember, A B C D E F
Why is ? A B C D E F
As a result, ACE BDF by? A B C D E F
C D by… A B C D E F
As a result, A B by… A B C D E F
Theorem 6-19: If a quadrilateral is an isosceles trapezoid, then each pair of base ’s is . A B C D E F
Make sure you can… • Given one angle of an isosceles trapezoid, find the remaining 3 angles.
AC BD because? A B E C D
C D by? A B E C D
If we want to prove ’s ACD and BCD are congruent, what do they share? A B E C D
ACD BCD by A B E C D
AD BC by A B E C D
Theorem 6-20: If a quadrilateral is an isosceles trapezoid, then its diagonals are A B E C D
The return of midsegments A midsegment of a trapezoid connects the midpoints of the legs (non parallel sides) and is the mean value of the 2 bases (parallel sides)
The return of midsegments A midsegment of a trapezoid connects the midpoints of the legs (non parallel sides) and is the mean value of the 2 bases (parallel sides)
In addition… A midsegment of a trapezoid connects the midpoints of the legs (non parallel sides) and is the mean value of the 2 bases (parallel sides)
In addition… Much like triangles, the midsegment is parallel to the sides it does not touch.
So find its length? • Add the bases and divide by 2.
Working backwards • Formula:
Working backwards • Formula: • Midsegment =
Plug in the length of the midsegment. • Formula: • Midsegment =
Plug in the length of a base. • Formula: • Midsegment =
Solve for the remaining base • Formula: • Midsegment =
Solve for the remaining base • Or • Arithmetically, multiply the length of the midsegment by 2 and subtract the length of the given base.
Here’s a problem I enjoy. • Given an isosceles trapezoid whose midsegment measures 50 cm and whose legs measures 24 mm. Find its perimeter.