Recall that the area of a trapezoid is determined by the equation

The area of the glass panel therefore should be the area of the trapezoid, minus the two area of the rectangle that has been cutout.
Given that
a = 28 1/4 inches
b = 16 1/4 inches
h = 8 inches
Area of rectangle = 12 3/8 square inches
Then the area of the glass panel is

Therefore, the area of the glass panel is 153 1/4 square inches.