Answers by visitors named: arghhh - correction - Reiny

the dangers of a simple typo, and the to copy-and-paste it ... whenever you see 1/65636 it should say <b>1/65536> so the final fraction is 2033136/65536 = 127071/4096 </b>

Use the property that in a cyclic quad, the opposite angles add up to 180° Let me know what you get.