In the figure, YZAB is a parallelogram. AD, DE and YZ are straight lines. YBC is an isosceles triangle.
- Find ∠a.
- Find ∠b.
(a)
∠ADY = ∠ZYE = 62° (Corresponding angles, YZ//DA)
∠DCY
= 180° - ∠ADY - ∠DYC
= 180° - 62° - 21°
= 97° (Angles sum of triangle)
∠BCY
= 180° - 97°
= 83° (Angles on a straight line)
∠CBY = ∠BCY = 83° (Isosceles triangle)
∠a
= ∠CBY
= 83° (Corresponding angles, ZA//YB)
(b)
∠b
= 180° - 83° - 83°
= 14° (Isosceles triangle YBC)
Answer(s): (a) 83°; (b) 14°
