Answer:
or 4.4721...
Explanation:
Let's pretend to draw a diagonal line straight from A to C, for a visual reference.
Point A is at (-3, 2)
Point C is at (1, 4)
You could use the distance formula...

or you could use Pythagorean Theorem,
, which might seem easier.
The rise of our diagonal line is 2 units, and the run is 4.
2^2=4 and 4^2= 16
4+16=20
= 4.4721...