ABCD is a quadrilateral and OADC is a trapezium in which OA // DC and ∠BAD = 107°, ∠ADC = 124°, ∠BCD = 65° and DC = DA. Find
- ∠ABO
- ∠DAO
- ∠ACD.
(a)
∠ABO
= 360° - 124° -107° - 65°
= 64° (Sum of angles in a quadrilateral)
(b)
∠DAO
= 180° - 124°
= 56° (Interior angles, AO//DC)
(c)
∠ACD
= (180° - 124°) ÷ 2
= 56 ÷ 2
= 28° (Isosceles triangle)
Answer(s): (a) 64°; (b) 56°; (c) 28°