Answer: 6.71
Step-by-step explanation
Check out the diagram below. I have added red segments to form a right triangle.
- a = 3 = vertical leg
- b = 6 = horizontal leg
- c = unknown hypotenuse = distance from point A to point B
Use the pythagorean theorem to find c.

The hypotenuse is roughly 6.71 units long.
The distance from A to B is approximately 6.71 units.