The figure, not drawn to scale, O is the centre of the circle and EK // FJ // GH. Find
- ∠DOG
- ∠DJO
(a)
∠KOF
= 180° - 94°
= 86° (Interior angles, EK//FO)
∠OGJ = ∠OJG = 29° (Isosceles triangle)
∠FOG
= 29° + 29°
= 58° (Exterior angle of a triangle)
∠DOG
= 86° + 58°
= 144°
(b)
∠JOG
= 180° - 29° -29°
= 122° (Isosceles triangle)
∠DOJ
= 360° - 144° - 122°
= 94° (Angles at a point)
DO = OJ = Radius
∠DJO
= (180° - 94°) ÷ 2
= 86° ÷ 2
= 43° (Isosceles triangle)
Answer(s): (a) 144°; (b) 43°
