Essential Quote: It’s a trap! 8-5: Trapezoids Essential Quote: It’s a trap!

8-5: Trapezoids Trapezoid: A quadrilateral with exactly one pair of parallel sides. Bases: The pair of parallel sides in a trapezoid Legs: The nonparallel sides of a trapezoid Base Angles: Pairs of angles that lie on the same base. base angles base leg leg base base angles

8-5: Trapezoids Median: The segment that joins the midpoints of the legs. The median of a trapezoid it equal to one half the sum of the two bases Example: Find MN if DE = 12 and FG = 18 ½(12 + 18) ½(30) MN = 15 D E MN = ½(DE + GF) M N G F

8-5: Trapezoids In some case, you will be asked to find the length of a leg given the median and the other leg Example: Find FG if MN is a median, MN = 22 and DE = 14 22 = ½(14 + FG) 44 = 14 + FG FG = 30 D E MN = ½(DE + GF) M N G F

8-5: Trapezoids ISOSCELES TRAPEZOID: A trapezoid where the two legs are congruent. In this case, each pair of base angles are congruent. Example: Find the missing angles in trapezoid TRAP P and A are base angles Since this is an isosceles trapezoid, the base angles are equal P = 60 T and R are also equal A trapezoid is a quadrilateral, meaning its angles add up to 360˚. x + x + 60 + 60 = 360 2x + 120 = 360 (combine like terms) 2x = 240 (subtract 120 each side) x = 120 (divide by 2) T = 120 and R = 120

8-5: Trapezoids Assignment Worksheet 8-5