선분의 중점을 작도하여라.(Construct the center of line segment.) : https://goo.gl/gwm9gq AlgeoMath : http://me2.do/GFGmehgn YouTube: https://youtu.be/ft4NmSbYNNU GeogebraTube : https://ggbm.at/ah563wpm ggb problem : https://goo.gl/AtSBQn[br][br]기하작도문제 : https://ggbm.at/jFazZw2g 수학자료실 강의실 : https://goo.gl/czyJLW YouTube Channel : https://goo.gl/JpzU5i twitter : https://twitter.com/mineungi