Q:

Is it correct to put 'to be' at the end of question?

For example, I could ask:

How accurate is that answer?

But would it be correct to say:

How accurate that answer is?

A:

The first way is correct.

How accurate is that answer?

The second way would be correct if it was a part of an indirect question. For example:

Could you tell me how accurate that answer is?

One thing to note here is when to put a question mark. You see, when the first part of this complex sentence is not a question then you do not put a question mark at the end.

I am wondering how accurate that answer is.

Or as Weather Vane said, it can be used as an exclamation, but then it is not a question:

How accurate that answer is!

See more:
http://www.perfect-english-grammar.com/indirect-questions.html

A:

The first way is correct.

How accurate is that answer?

The second way could be used as an exclamation but not as a question.

How accurate that answer is!

