PSLE In the figure, CDEF is a parallelogram. AFC and BFE are straight lines and AB = BC. ∠ABF = 30° and ∠DEF = 55°.
- Find ∠EFC.
- Find ∠FBC.
(a)
∠EFC
= 180° - 55°
= 125° (Interior angles)
(b)
∠AFB
= ∠EFC
= 125° (Vertically opposite angles)
∠BAF
= 180° - 125° - 30°
= 25° (Angles sum of triangle)
∠BCF = ∠BAF (Isosceles triangle)
∠ABC
= 180° - 25° - 25°
= 130° (Angles sum of triangle)
∠FBC
= 130° - 30°
= 100°
Answer(s): (a) 125°; (b) 100°