AHEM!! *Amok gets out his old professor robes and puts on his mean face*
Guys, you aren't supposed to be giving him the answer! Giving hints is fine, but how is leading him by the nose step for step allowing him to learn it? I'm ashamed of all of you! 😉
I'm assuming you already have the formula after all the web pages you've been given 😉.
As for determining the proper angle, think about how to do that for a second. Since we know its between 0-90 degrees, what do you think would be a good approach to determining that? *Amok takes off his old professor robes and hands him the answer on a silver platter* Try starting with the midpoint at 45 and then doing a point to each side of that, say at 40 and 50 and seeing how they compare 😉.