Area of a trapezium


Area Of A Parallelogram Show

Area of a trapezium


  • A trapezium is a 4 sided shape in which one pair of opposite sides is parallel: a trapezium
  • The parallel sides are called the bases: b1 and b2.
  • The distance between the bases is called the height: h.
  • The equation for the area of a trapezium is: area = \frac{(b_1 + b_2)h}{2}


  • If we duplicate the trapezium and rotate it: a duplicated and flipped trapezium
  • Then we see that the two trapeziums together form a parallelogram.
  • The area of a parallelogram is: area = base * height
  • Which in our case is: area = (b_1 + b_2)h
  • And we just divide this by two (as we only want the area of one of the trapeziums): area = \frac{(b_1 + b_2)h}{2}

Code (Python)

base1, base2 = 4, 2
height = 3

area = (base1 + base2) * height / 2
print(area) # prints 9.0