A trapezoid has parallel sides 13 and 21 cm long. The longer of the two nonparallel sides is 17 cm and the shorter is perpendicular to a parallel side. What is the area of the trapezoid?

Answer 1

make a sketch.
split the figure into a rectangle and a right-angled triangle.
in the triangle the base will be 21-13 or 8 cm
and the hypotenuse is 17
let the height be h
h^2 + 8^2 = 17^2
h^2 = 225
h = 15

area = rectangle + triangle
= 13(15) cm^2 + (1/2)(8)(15)
= 255 cm^2