TST III 2009, Problema 1
Posted: Thu May 21, 2009 11:53 am
Fie ABCD un patrulater circumscriptibil in care AB si CD se intersecteaza in M, AC si BD se intersecteaza in N. Stiind ca AD > max{AB,BC,CD}, aratati ca
\( 90^{\circ}<m(\angle AND) < 90^{\circ}+\frac{1}{2}m(\angle AMD). \)
\( 90^{\circ}<m(\angle AND) < 90^{\circ}+\frac{1}{2}m(\angle AMD). \)