6.6. Trapezoids http://www.ck12.org
In an isosceles trapezoid, base angles are congruent.
(^6) B∼= (^6) Cand (^6) A∼= (^6) D
m^6 B=m^6 C= 38 ◦
38 ◦+ 38 ◦+m^6 A+m^6 D= 360 ◦
m^6 A=m^6 D= 142 ◦
Vocabulary
Atrapezoidis a quadrilateral with exactly one pair of parallel sides. Anisosceles trapezoidis a trapezoid where the
non-parallel sides and base angles are congruent. Themidsegment (of a trapezoid)is a line segment that connects
the midpoints of the non-parallel sides.
Guided Practice
T RAPan isosceles trapezoid.
Find:
1.m^6 T PA
2.m^6 PT R
3.m^6 PZA
4.m^6 ZRA
Answers:
1.^6 T PZ∼=^6 RAZsom^6 T PA= 20 ◦+ 35 ◦= 55 ◦.
2.^6 T PAis supplementary with^6 PT R, som^6 PT R= 125 ◦.
3. By the Triangle Sum Theorem, 35◦+ 35 ◦+m^6 PZA= 180 ◦, som^6 PZA= 110 ◦.
4. Sincem^6 PZA= 110 ◦,m^6 RZA= 70 ◦because they form a linear pair. By the Triangle Sum Theorem,m^6 ZRA=
90 ◦.
Interactive Practice
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/113035