(a)[2]
The value of $x$ is [BLANK] because [BLANK].
(b)[1]
Angle $ABC = 90^{\circ}$ because [BLANK].
(c)[2]
The value of $y$ is [BLANK] because [BLANK].
Mathematics 0580 · IGCSE · Circle theorems I
Circle theorems I — practice question
Points A, B and C lie on a circle with centre O and diameter AC. The diagram shows angle at A is 65^{\circ}, angle at B is x^{\circ}, and angle at C is y^{\circ}. It is labelled NOT TO SCALE.