To find the area of the trapezoid, first we need to make an exact triangle to the other side of the trapezoid, just like in the diagram is showing, ( so you will have 2 triangles in the trapezoid, thinks about that the triangle that is on the diagram is reflecting to the other side) then we have a rectangle on the center of the trapezoid, we use the area formula which is would be 8x13=104, then we take the area formula of the triangle and substitute, which would be (1/2)8x4=16, we multiply 16 by 2 to get 32, this would be the area of the two triangles plus the area of the rectangle which is 104 gives a total of 136 cm2