Surya Siddhanta
लम्बाक्षज्ये तयोश् चापे लम्बाक्षौ दक्षिणौ सदा ॥ मध्यच्छाया भुजस् तेन गुणिता त्रिभमौर्विका ॥
The Bhuja of the shadow of the Gnomon at noon is the same as the shadow itself. Multiply the Radius by that Bhuja and divide the product by the hypothenuse of the said shadow; the quotient will be the sine of the zenith distance: . -
english translation
lambAkSajye tayoz cApe lambAkSau dakSiNau sadA ॥ madhyacchAyA bhujas tena guNitA tribhamaurvikA ॥
hk transliteration by Sanscript