The parallel sides of a trapezium are 65 m and 40m. non parallel sides are 39m and 56m. find the area of the trapezium.
Draw the figure. If the height is h, then you have a 40-by-h rectangle in the center, with extra lengths of x and 25-x on the longer base.
x^2+h^2 = 56^2
(25-x)^2+h^2 = 39^2
x^2-56^2 = (25-x)^2 - 39^2
x = 224/5
so, h^2 = 56^2-x^2 = 28224/25
h = 168/5
so, the area is (40+65)/2 * 168/5 = 1764