BCDE is a quadrilateral and OBED is a trapezium in which OB // ED and ∠CBE = 111°, ∠BED = 126°, ∠CDE = 66° and ED = EB. Find
- ∠BCO
- ∠EBO
- ∠BDE.
(a)
∠BCO
= 360° - 126° -111° - 66°
= 57° (Sum of angles in a quadrilateral)
(b)
∠EBO
= 180° - 126°
= 54° (Interior angles, BO//EC)
(c)
∠BDE
= (180° - 126°) ÷ 2
= 54 ÷ 2
= 27° (Isosceles triangle)
Answer(s): (a) 57°; (b) 54°; (c) 27°