ex 10 . SvP aidez moi .

aCd = 180°-(85°+35°)
       = 60°

d'apres le codage dCb = aCd

dCb = 60°

cDa+cDB = 180°
85°+cDb = 180°
cDB = 95°

aBc = 180°-(60°+95°) = 25°