Once the Ascending degree is obtained, Bhava Sphuta Ganitha or the computation of House Division becomes easy.
We have said that 180 degrees away from the Ascendant is the Descendant & 180 degrees away from the MC is the IC, the Patala Lagna.
So we have now 4 mathematical points on the Circle. Divide the quadrants by 3 and we get the starting and the end of 12 houses !
This type of Bhava Ganitha is attributed to Sripathi in the Indian system and in the Western system, there are many methods of computation, namely the sytems of Regiomontanus, Companus & Placidus !