Online Geometry theorems, problems, solutions, and related topics.
See complete Problem 71Cyclic Quadrilateral, Angles. Level: High School, SAT Prep, College geometryPost your solutions or ideas in the comments.
ABCD is a cyclic quadrilateral therefore angle beta and angle BCD are supplimentary. So beta + BCD = 180 degrees. Also, alpha + angle BCD = 180 degrees because they lie on a straight line. therefore alpha equals beta.Can anyone tell me if this is right?
Yes, it is right. Q.E.D.
Video-solutionhttp://www.youtube.com/watch?v=D-DFhH8XYgMNote that the reciprocal is true.