=+7-20.

A south-facing window is 4 ft wide by 6 ft tall and is set back into the wall a distance of 1 ft.

For Shreveport, LA, estimate the percentage of the window that is shaded for

(a) April 21, 9:00 A.M. solar time

(b) July 21. 12:00 P.M. solar time

(c) September 21, 5:00 P.M. solar time