triangle

Let angle ABC be x

angle ACB = 2 angle ABC = 2x
angle BCA = 3 angle ACB = 3 (2x) = 6x

angle ABC + angle ACB + angle BCA = 180 deg (because angles of traingle)
x + 2x + 6x = 180deg
9x = 180deg
x = 20deg

so,
angle ABC = 20deg
angle ACB = 40deg
angle BCA = 120deg

你會唔會寫錯題目呀?!

angle BCA 理應等於 ANGLE ACB喎，

而且條問題都冇提供ANGLE CAB/ BAC的資料，

計唔到喎！