PSLEIn the figure, ABCD is a parallelogram. AYD and YCZ are straight lines. ∠ZCD = 150°, ∠ADC = 42° and ∠ACY = 18°.
- Find ∠BCZ.
- Find ∠BAC.
(a)
∠BCD
= 180° - 42°
= 138° (Interior angles)
∠BCZ
= 360° - 150° - 138°
= 72° (Angles at a point)
(b)
∠DCY
= 180° - 150°
= 30°(Angles on a straight line)
∠BAC
= ∠ACD
= 30° + 18°
= 48° (Alternate angles)
Answer(s): (a) 72°; (b) 48°