A Romanesque window has the shape of a rectangle surmounted by a semicircle as on the figure above. Our goal is to determine the dimensions of the window that allow the most light to pass if the window perimeter measures 6m

how can I

a) give an expression to the perimeter (outside) of such a window, in terms of variables x and y

Perimiter = 6 m =m.

b) Give an expression for the surface area of such a window, in terms of variables x and y

Aire =m^2

c) With these formulas, and the information given, determine the dimensions of such a window that maximizes the area of its surface.