Surya Siddhanta
विषुवच्छाययाभ्यस्तः कर्णो मध्याग्रयोद्धृतः । स्वक्रान्तिज्या त्रिजीवाघ्नी लम्बज्याप्ताग्रमौर्विका ॥
The sine of the declination (of the Sun) multiplied by the radius and divided by the cosine of the latitude becomes the sine of amplitude. Multiply this sine by tbe hypothenuse of the shadow at a given time and divide the product by the radius: the quantity obtained is the sine of amplitude in digits (reduced to the hypothenuse of the shadow at the given time).
english translation
viSuvacchAyayAbhyastaH karNo madhyAgrayoddhRtaH । svakrAntijyA trijIvAghnI lambajyAptAgramaurvikA ॥
hk transliteration by Sanscript