सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

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Bb = Sama-S'anku, and Dd unmandala S'anku. O₂b is not
actually the Agrajyā but parallel and equal to it, since
Agrajyā is the H sine of SE of fig. 21, which is the per-
pendicular from S on Eω. Similarly do₄ is not the second
segment of Agrajyā but a parallel and equal segment.
Thus Bb is the perpendicular distance between EE' and
FF' ie. Eω and a parallel through F to Eω (fig. 21.)
Dd is the perpendicular distance between DD' and BB';
bo₂ is the perpendicular distance between Eω and SS'; do₄
the perpendicular distance between DD' and SS' (fig. 21) ;
Bo₂ the perpendicular distance between FF' and SS' ; Do₄
the perpendicular distance between BB', SS'. In this
fig. 39, O₁A is called Hṛti, Co₃ = Ishta-Hṛti or any arbitrary
hṛti. Taddhṛti Hṛti and Kujyā are special cases of
Ishtahṛti. Hṛti is the maximum of Ishtahṛti. Calling
Aa, Bb, Cc, Dd S'ankus in general ao₁, bo₂, co₃, do₄ are
called S'ankutalas. Aa is called Dinārdha-S'anku or the
S'anku of the mid-day ; whereas Dd is the unmandala-
S'anku and Bb Sama-S'anku. Cc is called Ishta-S'anku.
Perpendiculars from A, B, C, D on the plane of the prime
vertical are called S'anku-bhujas. Since B is on the
prime-vertical itself, the S'anku-bhuja is zero and at
this point BO₂ is Agrajyā. In the arbitrary case at C,
the perpendicular from C on the plane of the prime-
vertical being S'anku-bhuja, which is equal to the per-
pendicular from C on Eω, and Co₃ being the S'anku-tala,
and since the perpendicular distance between ML and
Eω is the Agrajyā, which is equal to the sum of O₃ C and
the S'anku-bhuja S'anku-tala + S'anku-bhuja = Agrajyā.
(10) which is a different expression of (5). We shall
present this analytically. Putting S'anku = H cos z, and
using the latitudinality of Cco₃ (H cos z) / 12 = Co₃ / s = Co₃ / K
applying similarity with the first fundamental latitudinal
triangle where s = equinoctial shadow, and K the
Viṣuvat-Karṇa. Hence we have