Clearly
`Delta IOQ` and `Delta I_(2) Q` are congruent
and `Dleta IOP` and `Delta II_(1)P` are congurent
So `II_(1) = IO` and `IO = II_(2)`
Hence, `II_(1) = IO = II_(2)`
So, `I_(1)` and `I_(2)` and `O` lie on the circumference of a circle with centre `I`.
