"How" can be used for emphasis—how cool is that!
English speakers like to use strong language, and one way is like this:
How long was that meeting!
Here are some other examples:
- How funny is he!
- How hard was that test!
- How hot is it today!
These may look like questions but they are actually strong statements. The difference between these as questions and these as exclamations, is intonation.
If "How long was that meeting?" is a question, your tone should rise at the end—it is the typical intonation for a question.
But for example, if you and your colleague are leaving the office after a four-hour meeting, you could say, "How long was that meeting!" In this case, it is an exclamation. You should stress the main adjective (in this case, "long"), by saying it longer and stronger, and your tone should fall on the last word.
The same pattern is found in phrases that end in "isn't it" or "wasn't it." In fact, using that pattern is a very common way to respond to the first phrase:
A: How funny was that movie!
B: It was funny, wasn't it!
Though what A and B both said could be used as questions, here, they aren't questions at all.
So, try using this pattern to make a strong statement in your next class. How easy is that!