Explicație pas cu pas:
a) ΔABC isoscel => ∢ACB = ∢ABC =
[tex]< ACB = < ABC = \frac{180 - 120}{2} = 30[/tex]
AM ⊥ AB => ∢BAM = 90°
[tex]< AMB = 90 - 30 = 60[/tex]
b)
[tex]\sin( < AMB) = \frac{AB}{BM} \\ \frac{ \sqrt{3} }{2} = \frac{12}{BM} \\ BM = \frac{2 \times 12}{ \sqrt{3} } = \frac{24 \sqrt{3} }{3} \\ = > BM = 8 \sqrt{3} \: cm[/tex]
