Needless to say I am awful at math. I am trying to figure what the degree of angle is for one of the brooder doors i have to build. left side: 28 3/8" right side: 20.5" base: 46 1/8" top(angled part): 46.75" I am hoping someone can tell me how to go about finding the angle. searched all over about right trapezoids/trapeziums, etc. would Really appreciate any help.