Noori, this is a multi post from a while ago:
https://web2.0calc.com/questions/chords-uv-wx-and-yz-of-a-circle-are-parallel-the
https://web2.0calc.com/questions/yo-cphill-do-ur-thing-geo-help
https://web2.0calc.com/questions/geometry-please-help-thanks
These are 3 of them on tis site only. The correct answer, as many more than decent answerers have stated, is 58.