Answer:
5 units
Step-by-step explanation:
Let's assume point (5,1) to be C
according to the picture we know AC= 3 and BC=4
Applying pythagorean theorem: a^2+b^2=c^2
(AC)^2+(BC)^2=(AB)^2
3^2+4^2=(AB)^2
9+16= (AB)^2
AB^2=25
AB=5
