May 23rd, 2018, 02:14 PM | #1 |
Newbie Joined: May 2018 From: house Posts: 1 Thanks: 0 | what is the value of X
I haven't done basic math, especially geometry for almost 30 years. My kid dared me to solve this problem. To be honest, I don't have a clue. If I break this down to 2 triangles, I can only find an angle of 80 degrees. But what is the value of X? It's somewhere in the range of 25 - 50 degrees but I'm just guessing. I don't want to admit that I forgot basic math because I rag on kids all the time that older generations are smarter. Thanks in advance. |
May 23rd, 2018, 02:24 PM | #2 |
Math Team Joined: Dec 2013 From: Colombia Posts: 7,636 Thanks: 2621 Math Focus: Mainly analysis and algebra | https://revisionmaths.com/gcse-maths...ircle-theorems Section Angle at the Centre just over halfway down. |
May 23rd, 2018, 02:30 PM | #3 |
Senior Member Joined: Oct 2009 Posts: 771 Thanks: 278 | |
May 23rd, 2018, 03:53 PM | #4 |
Global Moderator Joined: Dec 2006 Posts: 20,472 Thanks: 2039 | AnglesInCircle.PNG As the angles at O add to 360$^\circ\!$, 360$^\circ\!$ = 100$^\circ\!$ + (180$^\circ\!$ - 2m) + (180$^\circ\!$ - 2n) = 100$^\circ\!$ + 360$^\circ\!$ - 2m - 2n. Hence $x$ = m + n = (2m + 2n)/2 = 100$^\circ\!$/2 = 50$^\circ\!$. |