PSLE In the figure, CDEF is a parallelogram. AFC and BFE are straight lines and AB = BC. ∠ABF = 31° and ∠DEF = 59°.
- Find ∠EFC.
- Find ∠FBC.
(a)
∠EFC
= 180° - 59°
= 121° (Interior angles)
(b)
∠AFB
= ∠EFC
= 121° (Vertically opposite angles)
∠BAF
= 180° - 121° - 31°
= 28° (Angles sum of triangle)
∠BCF = ∠BAF (Isosceles triangle)
∠ABC
= 180° - 28° - 28°
= 124° (Angles sum of triangle)
∠FBC
= 124° - 31°
= 93°
Answer(s): (a) 121°; (b) 93°