Question 13341
Great problem. The easiest way, by my opinion, is to use the Distance Formula (a manipulation of the Pythagoras Theorem if you look closely):

<IMG SRC="http://www.algebra.com/cgi-bin/plot-formula.mpl?expression=D+=+sqrt%28%28x1+-+x2%29%5E2+%2B+%28y1+-+y2%29%5E2%29&x=0003&">

In our case: x1 = 9, x2 = 2, y1 = 5, y2 = 6

Therefore:

<IMG SRC="http://www.algebra.com/cgi-bin/plot-formula.mpl?expression=D+=+sqrt%28%289-2%29%5E2+%2B+%285+-+6%29%5E2%29&x=0003&">

which simplified gives us:

<IMG SRC="http://www.algebra.com/cgi-bin/plot-formula.mpl?expression=D+=+sqrt%2850%29&x=0003&">

And simplified further gives us:

<IMG SRC="http://www.algebra.com/cgi-bin/plot-formula.mpl?expression=5sqrt%282%29&x=0003&">

Though I would leave it like that for precision some people prefer it to be rounded off to 3 significant figures, which would give us:

D = 7.07