Answer:
You would want to do the square root of 361 which is 19
Hope This Helps!
ps. no, I'm not stalking u I just clicked on the next question from your last one.
The slope of these points is 4/3
They all add up to 2.5 maybe u have to simplify?
You can make some algebraic equations and solve it.
The first would be:

The second would be

You can then rearrange the second into

And subsitute it into the first like so:

After that, distribute the y into the parantheses.

Subtract the 21 on both sides and multiply by -1 on both sides:

You then can factor it into:

With Zero Product Property, we can determine y to be either -3 and 7. Since the variables are interchangable, you can say the same about x, just that whatever x is, y must be the other value.
Thus, the answer is 7 and -3.