Trapezoids

1
Lesson 5-5

• Trapezoids
• and
• Kites

2
The Trapezoid
A quadrilateral with EXACTLY ONE pair of parallel
sides.
3
The Trapezoid
Bases
Legs
A quadrilateral with EXACTLY ONE pair of parallel
sides.
4
The Isosceles Trapezoid
Legs
A trapezoid with congruent legs.
5
Isosceles Trapezoid
Trapezoid
6
Isosceles Trapezoid
Trapezoid
7
Is this a trapezoid?
8
NO
The quadrilateral does not have EXACTLY one pair
of parallel sides.
9
Flow Chart
Quadrilaterals
Parallelogram
Rhombus
Rectangle
Square
Where do trapezoids belong?
10
Flow Chart
Quadrilaterals
Parallelogram
Isosceles Trapezoid
Rhombus
Rectangle
Square
11
The MEDIAN of a trapezoid is the segment that
joins the midpoints of the legs.
12
Note difference between the MEDIAN of a trapezoid
and the median of a triangle.
13
Base angles of an isosceles triangle are
congruent.
B
A
D
C
Given trapezoid ABCD Prove ?A ? ?B
14
Base angles of an isosceles triangle are
congruent.
E
B
A
D
C
Plan Through point D draw DE to CB.
15
Base angles of an isosceles triangle are
congruent.
E
B
A
D
C
Plan Through point D draw DE to CB. BCDE is
a
16
Base angles of an isosceles triangle are
congruent.
E
B
A
D
C
Plan Through point D draw DE to CB. BCDE is
a so DE ? CB .
17
Base angles of an isosceles triangle are
congruent.
E
B
A
D
C
Plan Through point D draw DE to CB. BCDE is
a so DE to CB . Since ?ADE is isosceles
then ?AED ? ?A.
18
Base angles of an isosceles triangle are
congruent.
E
B
A
D
C
Plan Through point D draw DE to CB. BCDE is
a so DE to CB . Since ?ADE is isosceles
then ?AED ? ?A. ?AED ? ?B because they are
corresponding angles.
19
The median of a trapezoid is . . .(1) parallel
to the base(2) has length equal to the average
of the two bases.
IF
20
The median of a trapezoid is . . .(1) parallel
to the base(2) has length equal to the average
of the two bases.
THEN
x
2x
3x