Well of course you can use the distance formula but do realize that the distance formula is not really covered by the Original Guide. Hence, they had to provide a 3rd coordinate to make it a right angled triangle so that you could use the pythagorus theorem. Using the distance formula:

For 2 points: A & B, Distance between A and B

=\sqrt{({(x_1-x_2)}^2 + {(y_1-y_2)}^2)}Where

A=(x_1,y_1) &

B=(x_2,y_2)In the question above

Y=(-4,3) &

Z=(2,-3)Distance between 2 points, Y & Z, on the coordinate system

=\sqrt{({(-4-2)}^2 + {(3+3)}^2)}Which is

=\sqrt{(6^2 + 6^2)}Which is

=\sqrt{72}Which is

=6\sqrt{2}So Yes, to answer your question, info about

Y &

Z alone is sufficient

"if you know the formula for deriving the distance between two coordinates", but otherwise you need to know a third point to first establish it is a right angled triangle. Works either ways. I have seen numerous statistics questions where GMAT actually gives you the formula for calculating the sum of the series, even though we need to know it to solve quite a few question on the GMAT. Either ways, your pick. Answer still remains the same

=6\sqrt{2} and not

6!

_________________

"Nowadays, people know the price of everything, and the value of nothing." Oscar Wilde