If you know the lengths of the three sides, then the cosine is... erm...

Ahhh! I don't get any of this

"Maths is easy if you just remember the formulas and apply them"!?

That's something only people who are good at studying would say!

For those of us who struggle, that's the hard part!

Waaah! Even though I'm one of the true elite and everything!

Tsurugi is feeling down, thinking her teaching method is bad, so...

Could you at least pretend to understand?