(a)[1]
Determine angle $AOC$.
(b)[1]
Determine angle $ABC$.
(c)[1]
Determine angle $DAC$.
(d)[1]
Determine angle $OAB$.
Mathematics 0580 · IGCSE · Circle theorems II
Circle theorems II — practice question
Points A, B and C lie on a circle with centre O. DE is a tangent to the circle at A. Angle $ACO$ is $35^{\circ}$ and angle $BCO$ is $40^{\circ}$. The diagram is marked NOT TO SCALE.