ma ajuta si pe mine cineva?
va rog..
se considera pct necoplanare A,B,C,D a.i. AB=AC=BD=CD=a.
a) aratatzi k AD_|_BC
b) dak P apartzine AB, Q apartzine AC, S apartzine BD, T apartzine CD a.i. AP=AQ=DS=DT. aflatzi natura patrulat PQST
c) daca, in plus, m(<BAC)=m(<ACD)=60grade, calc A maxima a patrulat PQST.