Aug 27, 2013 Thread starter #1 Albert Well-known member Jan 25, 2013 1,225 $\triangle ABC (with \,\, side \,\, length \,\, a,b,c)$ $if :2b<a+c$ $prove :2\angle B <\angle A +\angle C$

$\triangle ABC (with \,\, side \,\, length \,\, a,b,c)$ $if :2b<a+c$ $prove :2\angle B <\angle A +\angle C$