I'll give you a hint. A trapezoid is made up of 2 triangles and a square. Simply find the area of them and add them together.
This is some of the simplest math you can learn. The article I sent you gives a full explanation on it, yet you refuse to read it. I have no other solutions for you.
mathsisfun.com/algebra/trig-area-triangle-without-right-angle.html
https://www.mathsisfun.com/cuboid.html
This is the only answer you are going to get. https://www.mathsisfun.com/algebra/trig-area-triangle-without-right-angle.html
https://www.mathsisfun.com/algebra/trig-area-triangle-without-right-angle.html
Let's say x represents your number.
(4 * x - 4)* 1/3 = -6.
4 * x - 4 = -18
4 * x = -14
x = -3.5
Your number is -3.5
13 * 16.4 * 1/2 = [answer]
