Did you know that the word trapezoid comes from the Greek “τραπέζιον” (or trapeza) meaning “table,” with the suffix –oid meaning “to resemble?” Hmmm… Trapezoids
Definition of trapezoid… • Trapezoid: a quadrilateral consisting of exactlyonepair of parallel sides. OR a quadrilateral with two parallel sides of unequal length. • Using this definition, is a square also a trapezoid? A rectangle? A parallelogram?
Trapezoids: b1 = base 1 h = height leg leg Height – distance between the 2 bases. * Must be b2 = base 2 base base Area of trapezoid A = ½ h(b1 + b2) Height
Ex. 1 Find the area of the following trapezoid. 20in This is the height!! 30in 18in 36in A = ½ h(b1 + b2) = ½ (18in)(36in + 20in) = ½ (18in)(56in) = 504in2
What happens if you are given the area, but are missing one of the bases? = 4 in b1 4 in A = 22 in2 7 in
Find the height of the trapezoid. 35 m = 23 m h A = 1035 m2 55 m