Geometry Section 6-6 1112

Section 6-6
Trapezoids and Kites
Tuesday, April 29, 14

Essential Questions
• How do you apply properties of
trapezoids?
• How do you apply properties of kites?

Vocabulary
1.Trapezoid:
2. Bases:
3. Legs of a Trapezoid:
4. Base Angles:
5. Isosceles Trapezoid:

Vocabulary
1.Trapezoid: A quadrilateral with only one pair of
parallel sides
2. Bases:
4. Base Angles:

Vocabulary
parallel sides
2. Bases: The parallel sides of a trapezoid
4. Base Angles:

Vocabulary
parallel sides
3. Legs of a Trapezoid: The sides that are not parallel in a
trapezoid
4. Base Angles:

Vocabulary
parallel sides
trapezoid
4. Base Angles: The angles formed between a base and
one of the legs

Vocabulary
parallel sides
trapezoid
4. Base Angles: The angles formed between a base and
one of the legs
5. Isosceles Trapezoid: A trapezoid that has congruent
legs

Vocabulary
6. Midsegment of a Trapezoid:
7. Kite:

Vocabulary
6. Midsegment of a Trapezoid: The segment that
connects the midpoints of the legs of a trapezoid
7. Kite:

Vocabulary
6. Midsegment of a Trapezoid: The segment that
connects the midpoints of the legs of a trapezoid
7. Kite: A quadrilateral with exactly two pairs of
consecutive congruent sides; Opposite sides are not
parallel or congruent

Theorems
Isosceles Trapezoid
6.21:
6.22:
6.23:

Theorems
Isosceles Trapezoid
6.21: If a trapezoid is isosceles, then each pair of base
angles is congruent
6.22:
6.23:

Theorems
Isosceles Trapezoid
angles is congruent
6.22: If a trapezoid has one pair of congruent base
angles, then it is isosceles
6.23:

Theorems
Isosceles Trapezoid
angles is congruent
6.22: If a trapezoid has one pair of congruent base
angles, then it is isosceles
6.23: A trapezoid is isosceles IFF its diagonals are
congruent

Theorems
6.24 - Trapezoid Midsegment Theorem:
Kites
6.25:
6.26:

Theorems
6.24 - Trapezoid Midsegment Theorem: The midsegment
of a trapezoid is parallel to each base and its measure
is half of the sum of the lengths of the two bases
Kites
6.25:
6.26:

Theorems
Kites
6.25: If a quadrilateral is a kite, then its diagonals are
perpendicular
6.26:

Theorems
Kites
6.25: If a quadrilateral is a kite, then its diagonals are
perpendicular
6.26: If a quadrilateral is a kite, then exactly one pair of
opposite angles is congruent

Example 1
Each side of a basket is an isosceles trapezoid. If m∠JML =
130°, KN = 6.7 ft, and LN = 3.6 ft, ﬁnd each measure.
a. m∠MJK

Example 1
a. m∠MJK
m∠JML = m∠KLM

Example 1
a. m∠MJK
m∠JML = m∠KLM
360 − 2(130)

Example 1
a. m∠MJK
m∠JML = m∠KLM
360 − 2(130) = 100

Example 1
a. m∠MJK
m∠JML = m∠KLM
360 − 2(130) = 100
100/2

Example 1
a. m∠MJK
m∠JML = m∠KLM
360 − 2(130) = 100
100/2 = 50

Example 1
a. m∠MJK
m∠JML = m∠KLM
360 − 2(130) = 100
100/2 = 50
m∠MJK = 50°

Example 1
b. JL

Example 1
b. JL
JN = KN

Example 1
b. JL
JN = KN
JL = JN + LN

Example 1
b. JL
JN = KN
JL = JN + LN
JL = 6.7 + 3.6

Example 1
b. JL
JN = KN
JL = JN + LN
JL = 6.7 + 3.6
JL = 10.3 ft

Example 2
Quadrilateral ABCD has vertices A(5, 1), B(−3, −1), C(−2, 3),
and D(2, 4). Show that ABCD is a trapezoid and determine
whether it is an isosceles trapezoid.

Example 2
x
y

Example 2
x
y
A

Example 2
x
y
A
B

Example 2
x
y
A
B
C

Example 2
x
y
A
B
C
D

Example 2
x
y
A
B
C
D
We need AB to be parallel
with CD

Example 2
x
y
A
B
C
D
We need AB to be parallel
with CD
CB ≅ ADAlso,

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9 = 18

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9 = 18
BC = (−3+ 2)2
+ (−1− 3)2

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9 = 18
BC = (−3+ 2)2
+ (−1− 3)2
= (−1)2
+ (−4)2

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9 = 18
BC = (−3+ 2)2
+ (−1− 3)2
= (−1)2
+ (−4)2
= 1+16

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9 = 18
BC = (−3+ 2)2
+ (−1− 3)2
= (−1)2
+ (−4)2
= 1+16
= 17

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9 = 18
BC = (−3+ 2)2
+ (−1− 3)2
= (−1)2
+ (−4)2
= 1+16
= 17
CB ≅ AD

Example 2
A(5, 1), B(−3, −1), C(−2, 3), and D(2, 4)
m(AB) =
−1−1
−3− 5
=
−2
−8
=
1
4
m(CD) =
4 − 3
2 − (−2)
=
1
4
AD = (5 − 2)2
+ (1− 4)2
= (3)2
+ (−3)2
= 9 + 9 = 18
BC = (−3+ 2)2
+ (−1− 3)2
= (−1)2
+ (−4)2
= 1+16
= 17
It is a trapezoid, but not isoscelesCB ≅ AD

Example 3
In the ﬁgure, MN is the midsegment of trapezoid FGJK.
What is the value of x?

Example 3
MN =
KF + JG
2

Example 3
MN =
KF + JG
2
30 =
20 + JG
2

Example 3
MN =
KF + JG
2
30 =
20 + JG
2
60 = 20 + JG

Example 3
MN =
KF + JG
2
30 =
20 + JG
2
60 = 20 + JG
40 = JG

Example 4
If WXYZ is a kite, ﬁnd m∠XYZ.

Example 4
m∠WXY = m∠WZY

Example 4
m∠WXY = m∠WZY
m∠XYZ = 360 −121− 73−121

Example 4
m∠WXY = m∠WZY
m∠XYZ = 360 −121− 73−121 = 45°

Example 5
If MNPQ is a kite, ﬁnd NP.

Example 5
a2
+ b2
= c2

Example 5
a2
+ b2
= c2
62
+ 82
= c2

Example 5
a2
+ b2
= c2
62
+ 82
= c2
36 + 64 = c2

Example 5
a2
+ b2
= c2
62
+ 82
= c2
36 + 64 = c2
100 = c2

Example 5
a2
+ b2
= c2
62
+ 82
= c2
36 + 64 = c2
100 = c2
100 = c2

Example 5
a2
+ b2
= c2
62
+ 82
= c2
36 + 64 = c2
100 = c2
100 = c2
c =10

Problem Set

Problem Set
p. 440 #1-27 odd, 35-43 odd, 49, 65, 75, 77
“Do what you love, love what you do, leave the world a
better place and don't pick your nose.” - Jeff Mallett

Geometry Section 6-6 1112

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