TrapezoidsTrapezoids

Section 8-6

trapezoid – a quadrilateral with exactly one pair of parallel sides

The parallel sides are called bases. The nonparallel sides are called legs.

base

leg leg

base

isosceles trapezoid – a trapezoid that has congruent legs

Thms. 8-18 & 8-19Thms. 8-18 & 8-19Both pairs of base angles of an

isosceles trapezoid are congruent.The diagonals of an isosceles

trapezoid are congruent.

A B

CD

AC BD

The median of a trapezoid is the segment that joins the midpoints of its legs.

Theorem 8-20Theorem 8-20

The median of a trapezoid is parallel to the bases, and its measure is one-half the sum of the measures of the bases.

Joke TimeJoke Time

What’s big, gray, and wears glass slippers?

Cinderellaphant

Why do you rarely find mathematicians spending time at the beach?

Because they have sine and cosine to get a tan and don't need the sun!