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11 va roog dau coroana

11 Va Roog Dau Coroana class=

Răspuns :

11.
AB=4
BC=6
m(∡B)=60°        cos 60°=1/2
AC²=AB²+BC²-2×AB×BC×cos 60°
AC²=4²+6²-2×4×6×1/2
AC²=16+36-24
AC²=28
AC=√28=2√7

b/sin B=c/sinC
2√7/sin 60°=4/sin C
2√7/√3/2=4/sin C
2√7/√3/2=4/sin C
sin C=√3/√7