
This Page:: angles  Midsegment  area  Isosceles Trapezoid
Free Math Printable Worksheets : Activity
The two parallel lines are called the bases
The LegsThe two non parallel lines are the legs.
Example 2 of legs and the Bases
Adjacent Angles of Trapezoid
The angles on the same side of a leg are called adjacent angles such as $$\angle A $$ and $$ \angle D $$ are supplementary. For the same reason, $$ \angle B $$ and $$ \angle C $$ are supplementary.
Practice Problem
$$ \angle ZWX = 180 − 44 = 136° $$
$$ \angle MLO = 180124 = 56° $$
If LMNO is a trapezoid and its bases LO and MN are parallel then, $$ \angle MNO $$ and $$ \angle NOL $$ which must be supplementary however, the sum of these angles is not 180
111 + 68 ≠ 180
Area of Trapezoid
 Area = 7 × ½(4 +8)
 7 × ½(12)
 7 ×6
 42 square feet
Midsegment of Trapezoid
The midsegment of a trepzoid is
 parallel to both bases
 has length equal to the average of the length of the bases
To calculate the length of the midsgement find the average of the bases length of midsegment = (6+4)/2 = 5
The midsegment of a trapezoid is the segment that joins the midpoints of the nonparallel sides of a trapezoid.
In the trapezoid below, the midpoints of the nonparallel sides are points S and V. The midsegment is the red line segment from S to V.
The midsegment below can be found by
 calculating the lengths of the bases
 calculating the sum of the bases
 9+45 = 54
 Dividing the sum by 2
 ½(54) = 27
The length of the midsegment is 26.5
Practice Problems
Length of top base = 178 = 9
Length of bottom base= 200 =20
Sum of bases = 9 + 20 = 29
Divide sum of bases by 2 = ½(29) = 14.5
Therefore, the midsegment SV is 14.5 in length.
It is not a true midsegment because its length does not equal half the sum of the lengths of the bases.