The figure is not drawn to scale. ZBCD is a trapezium and ZB // DC. Given that ZD = ZA, ∠DZA = 78° and ∠ZBC = 102°.
- Find ∠BCD
- Find ∠ZAD
- Find ∠ADC
(a)
∠BCD
= 180° - 102°
= 78° (Interior angles, ZB//DC)
(b)
∠ZAD
= (180° - 78°) ÷ 2
= 102° ÷ 2
= 51° (Isosceles triangle)
(c)
∠ADC
= ∠ZAD
= 51° (Alternate angles, ZB//DC)
Answer(s): (a) 78°; (b) 51°; (c) 51°