▁solution ▁of ▁various ▁linear ▁equations ▁are ▁among ▁the ▁arithmetic ▁and ▁algebraic ▁topics ▁included . ▁A ry ab h ata ' s ▁general ▁solution ▁for ▁linear ▁ind et erm inate ▁equations , ▁which ▁Bh ask ara ▁I ▁called ▁k utt ak ara ▁(" p ul ver izer "), ▁consisted ▁of ▁breaking ▁the ▁problem ▁down ▁into ▁new ▁problems ▁with ▁success ively ▁smaller ▁coefficients — ess entially ▁the ▁E uclidean ▁algorithm ▁and ▁related ▁to ▁the ▁method ▁of ▁continued ▁fra ctions . ▁ ▁With ▁K ala - k ri ya ▁A ry ab h ata ▁turned ▁to ▁astronom y — in ▁particular , ▁tre ating ▁planet ary ▁motion ▁along ▁the ▁e cli ptic . ▁The ▁topics ▁include ▁definitions ▁of ▁various ▁units ▁of ▁time , ▁ecc ent ric ▁and ▁ep icy clic ▁models ▁of ▁planet ary ▁motion ▁( see ▁Hi pp arch us ▁for ▁earlier ▁Greek ▁models ), ▁planet ary ▁longitude ▁corre ctions ▁for ▁different ▁terrest rial ▁locations , ▁and ▁a ▁theory ▁of ▁" l ords ▁of ▁the ▁hours ▁and ▁days " ▁( an ▁ast ro log ical ▁concept ▁used ▁for ▁determ ining ▁prop it ious ▁times ▁for ▁action ). ▁ ▁A ry ab h ati ya ▁ends ▁with ▁spher ical ▁astronom y ▁in ▁G ola , ▁where ▁he ▁applied ▁plane ▁trig on ometry ▁to ▁spher ical ▁geometry ▁by ▁project ing ▁points ▁and ▁lines ▁on ▁the ▁surface ▁of ▁a ▁sphere ▁onto ▁appropriate ▁plan es . ▁Top ics ▁include ▁prediction ▁of ▁solar ▁and ▁lun ar ▁e cli ps es ▁and ▁an ▁explicit ▁statement ▁that ▁the ▁apparent ▁west ward ▁motion