Surya Siddhanta
दिग्भेदे मिश्रिताः साम्ये विश्लिष्टाश् चाक्षलिप्तिकाः । ताभ्यो +अक्षज्या च तद्वर्गम् प्रोज्झ्य त्रिज्याकृतेः पदम् ॥
Find the sine of the latitude, (just found); take the square of that sine from that of the Radius; the square root of the remainder is the cosine of the latitude. The sine of the latitude multiplied by 12 and divided by the cosine of the latitude gives the Palabhá or the equinoctial shadow.
english translation
digbhede mizritAH sAmye vizliSTAz cAkSaliptikAH । tAbhyo +akSajyA ca tadvargam projjhya trijyAkRteH padam ॥
hk transliteration by Sanscript