(√3 + 1)/8 the answer to the question
Let, the length = l
Width = l/2
Area = l * w = l * l/2 = l²/2
So, Your Final Answer would be A = l²/2
Hope this helps!
Area of the parallelogram = 20 x 16 = 320
Area of the triangle on top = 1/2 x 20 x 8 = 80
Total = 320 + 80 = 400 square inches