This is the 9806th most frequent Turkish word.
atacağını
"Atacağını" means "that you will throw" or "that he/she/it will throw," depending on the context.
Here, 'atacağını' is the future tense third person singular form of the verb 'atmak', meaning 'to throw'. It is used here to indicate the future action of throwing the letter into a mailbox.
Mektubunu hemen posta kutusuna atacağını söyledi.
He said he would immediately throw his letter into the mailbox.
In this sentence, 'atacağını' expresses the intent to throw something upward, in this case balloons into the air.
Yarın balonları havaya atacağını belirtti.
He stated that he would tomorrow release the balloons into the air.
In this example, 'atacağını' indirectly conveys the act of quitting as transforming or abandoning something metaphorically, illustrating the versatileness of the verb when expressed in context.