P6 Angles A001

/_ ABE = 60 ^o                  (ABE is an equilateral triangle)

/_ EBC = 80 ^o – 60 ^o

                   = 20 ^o

/_ FCB = /_ FBC     (Since the 3 sides of Triangles BCD and

                                  BCF are the same)

            = 20 ^o ÷ 2      (Since EC divides /_ ACB equally
                                   as ABE is an equilateral triangle)

            = 10 ^o

/_ BDC = 180 ^o – 20 ^o – 10 ^o

             = 150 ^o