Teacher2Teacher 
Q&A #1619 
View entire discussion [<< prev] [ next >>]
From: Loyd <Loydlin@aol.com> To: Teacher2Teacher Public Discussion Date: 2011010313:02:00 Subject: Re: 120 degree angle contruction? On 2007022717:17:31, emily wrote: > >I have a geometry project due, and I have to construct a 120 degree >angle only using a straightedge and a compass. can anyone help me?? > Go to this site and see the method for constructing a 30 degree angle. Add that to a 90 degree angle (by constructing a square) and you have a 120 degree angle. http://www.mathopenref.com/constangle30.html When I first saw this problem, I thought of my high school geometry when some of my friends tried to trisect an angle with only a staightedge and compass. So, my first thought was it would be impossible. But for a 30 degree angle, a neat construction is shown on the above web site that uses only a straightedge and compass.
Post a reply to this message

[Privacy Policy] [Terms of Use]
Math Forum Home 
The Math Library 
Quick Reference 
Math Forum Search