The figure, not drawn to scale, O is the centre of the circle and BG // CF // DE. Find
- ∠AOD
- ∠AFO
(a)
∠GOC
= 180° - 94°
= 86° (Interior angles, BG//CO)
∠ODF = ∠OFD = 31° (Isosceles triangle)
∠COD
= 31° + 31°
= 62° (Exterior angle of a triangle)
∠AOD
= 86° + 62°
= 148°
(b)
∠FOD
= 180° - 31° -31°
= 118° (Isosceles triangle)
∠AOF
= 360° - 148° - 118°
= 94° (Angles at a point)
AO = OF = Radius
∠AFO
= (180° - 94°) ÷ 2
= 86° ÷ 2
= 43° (Isosceles triangle)
Answer(s): (a) 148°; (b) 43°