Valmiki Ramayana Yuddha Kanda Sarga 2 Shloka 10
Original Shlokaदृष्टवातांतुपुरींलङ्कांत्रिकूटशिखरेस्थिताम् । हतंचरावणंयुद्धेदर्शनावधारय ।।6.2.10।।
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त्रिकूटशिखरे: on top of Trikuta mountain, स्थिताम्: situated, ताम्: that, लङ्कांपुरीम्: city of Lanka, दृष्टवा: after seeing, युद्धे: in war, तु: you, दर्शनात्: on having a look , रावणम्: Ravana, हतम्: is killed, अवधारय: can determine
"If the city of Lanka situated on top of Trikuta mountain is seen, you can be sure that Ravana is killed."