I found an image that corresponds to the above question. The shape was a rectangle. Its width is 7 units, its length is x. The shaded area of the rectangle forms a trapezoid.
Area of a trapezoid = [(a+b)/2] * h
63 sq. units = (7+x)/2 * 7 63/7 = (7+x)/2 9 = (7+x)/2 9*2 = 7 + x 18 = 7 + x 18 - 7 = x 11 = x
The value of x is 11 units. It is the length of the rectangle.
Area of the trapezoid = (a+b)/2 * h 63 = (7+11)/2 * 7 63 = 18/2 * 7 63 = 9 * 7 63 = 63