Well, I have no idea how inversion (on a circle - as you probably meant) works (yes I know, I'm an uneducated geometer), however I solved it by a mere angle-chasing (unspectacular but easy and stupit)
Well, Wala akong ideya kung paano pagbabaligtad (sa isang bilog na - habang ikaw ay malamang na sinadya) gumagana (yes alam ko, Ako ay isang walang pinag-aralan geomiter), subalit ako lutasin ito sa pamamagitan ng isang kusang-anggulo-habol (unspectacular ngunit madali at stupit)