2. Variant: in △ ABC, known B = 45 °, C = 60 ° and a = 12cm, solve triangle

2. Variant: in △ ABC, known B = 45 °, C = 60 ° and a = 12cm, solve triangle

∠A=180°-∠B-∠C=75°
Ad = BD = root 3CD
(1 + root 3 / 3) BD = a = 12cm
Ψ BD = ad = 18-6 radical 3 & nbsp; cm
Ψ AB = radical 2bd = 18 radical 2-6 radical 6 & nbsp; & nbsp; cm,
AC = 2 / root 3 × ad = 12 root 3-12 & nbsp; & nbsp; cm