Short answers, pulled from the story.
The word taka emerged from the Sanskrit term ́ta ńka, meaning silver coin. This linguistic root traveled across Central Asia to become a currency name in multiple languages including Middle Persian dāng and Turkic təñkə.
Sultan Shams al-Din Iltutmish established the silver tanka in the 13th century. Each coin weighed one tola equaling 96 rattis at 11.2 grams total while smaller billon jital coins contained only 48 units with approximately 3.5 grams combined weight.
Ibn Battuta observed the silver taka dominating Islamic Bengal in 1338 instead of the dinar. Provincial capitals across the kingdom hosted at least 27 mints producing these coins while Arakan served as a vassal state where the Bengal tanka circulated widely throughout the 16th and 17th centuries.
The Tibetan government began minting its own tangka starting in 1763/64 after King Indra Simha established the tanka standard in the prosperous Kathmandu Valley. China's Qing dynasty established official mints in the region during 1792 and Sino-Tibetan tangkas carried Chinese language inscriptions marking their imperial connection.
Bangladesh Bank officially introduced the modern Bangladeshi taka in 1972 following independence. This new currency replaced the Pakistani rupee at par after the end of the Bangladesh Liberation War with current versions bearing symbols ́ and Tk produced by Bangladesh's Security Printing Corporation.