2017-03-14T08:49:00ZFluxBBhttp://www.mathisfunforum.com/viewtopic.php?id=23786Simple. Show that quadrilateral IFBD is cyclic. And use the property of inscribed angle vs.measure of arc.Finished in two lines.]]>http://www.mathisfunforum.com/profile.php?id=2124862017-03-14T08:49:00Zhttp://www.mathisfunforum.com/viewtopic.php?pid=395632#p395632hi Geomtry.202
Welcome to the forum.
This problem re-appears every few months. Solution here:
]]>http://www.mathisfunforum.com/profile.php?id=676942017-03-14T08:02:40Zhttp://www.mathisfunforum.com/viewtopic.php?pid=395625#p395625Let the incircle of triangle ABC be tangent to sides BC, AC, and AB at D, E, and F, respectively. Prove that triangle DEF is acute. I haven't learned any trig yet. One of the hints were : Compute the angles of triangle DEF in terms of the angles of triangle ABC.
[I added the img tags so that the picture will show -bobbym]