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

244 Hṛti = O₁A = OO₁ + OA = Kujyā + H cos δ or Dhujyā VI since OO₁ = DO₄ = Kujyā. The line in the Equatorial plane cor- responding to Kujyā is Charajyā which is equal to R tan φ tan δ (13) so that we can write Kujyā = R sin δ tan φ = H sin δ tan φ (13'). Also from VI [Fig. 40] Antyā = R + Charajyā = R + R tan φ tan δ (14) which gives us the duration of half the day where R gives 6 hrs and Charajyā the increment in day due to φ and δ. [Fig. 40] Verse 18. To obtain the magnitudes of the various chords or the elements of the latitudinal triangles. The elements or the sides of all these latitudinal triangles are mutually derivable from similarity. Comm. Easy. Second half of Verse 18. The radius multiplied by the Kotis or Bhujas and divided by the Karnas gives H cos φ and H sin φ. Comm. The seven triangles except the second, of the eight latitudinal triangles are compared here with the second. Remembering Bhujas are the sides of the triangles opposite to φ and Kotis opposite to 90 − φ,