How to stop Siri from turning off after being quiet for a couple seconds?

I’ve noticed whenever Siri comes up with an answer to some question it’ll disappear if I’m quiet for about 15 seconds and I find it really annoying especially since I’m usually reading what it just sent me. Example: I asked Siri if the Casio fx-9750GII had matrices operations and it pops up with an answer (that I think is wrong because it’s for a different type of calculator or something) and then while I’m reading it trying to follow the steps it gives me it just disappears meaning I either have to just search it manually to actually read the rest of it, meaning Siri is useless, or ask it again.