Teach180 Post from lindjonath

LOC proof+continuing challenges
shout-outs: @CutTheKnotMath +MARShttps://t.co/3H6mVd4RfQ#teach180 #mtbos #iteachmath http://pic.twitter.com/wzZ1jY72KE

— Jonathan Lind (@lindjonath) September 15, 2017