ABCD is a quadrilateral and OADC is a trapezium in which OA // DC and ∠BAD = 113°, ∠ADC = 126°, ∠BCD = 62° and DC = DA. Find
- ∠ABO
- ∠DAO
- ∠ACD.
(a)
∠ABO
= 360° - 126° -113° - 62°
= 59° (Sum of angles in a quadrilateral)
(b)
∠DAO
= 180° - 126°
= 54° (Interior angles, AO//DC)
(c)
∠ACD
= (180° - 126°) ÷ 2
= 54 ÷ 2
= 27° (Isosceles triangle)
Answer(s): (a) 59°; (b) 54°; (c) 27°