Calculus Optimization Problem (Norman Window)?

A Norman window has the shape of a semicircle atop a rectangle so that the diameter of the semicircle is equal to the width of the rectangle. What is the area of the largest possible Norman window with a perimeter of 29 feet? There are all kinds of variants of this question on here already but no matter which equation i try or steps i follow i do not get the correct answer, so if someone could walk through my problem specifically i would really appreciate it.