Answer:
Square root of 13
Step-by-step explanation:
If y=x, that means that we can use any coordinates as long as it is true. I will use (1,1)
The distance formula is the square root of (x2-x1)^2+(y2-y1)^2
(3-1)^2=4
(4-1)^2=9
4+9=13
=Square root of 13
