What do you want? If you know the answer is 6, then you know your answer is wrong. If you want us to check your work and see where you went wrong, you will need to show your work!AND
The answer i have been obtaining is a=4
The formula to use was d = \sqrt(x2-x1)^2+(y2-y1)^2
in this case d being \sqrt 41
the actual answer is a= 6..