Question 1154084
<pre>{{{drawing(400,3500/13,-6,7,-4,5,

grid(1),circle(-5,4,.1),circle(6,-3,.1), line(-5,4,6,-3))}}}

Draw in the two lines in red:

{{{drawing(400,3500/13,-6,7,-4,5,
red(line(-5,4,-5,-3),line(-5,-3,6,-3)),
grid(1),circle(-5,4,.1),circle(6,-3,.1), line(-5,4,6,-3))}}}

Use the Pythagorean theorem:

Count the red horizontal and vertical sides of the triangle.

The vertical side is 7 units long and the horizontal side is 11
units long.

The length of the hypotenuse is the distance between the two points.

So 

{{{matrix(6,1,
c^2=a^2+b^2,
c^2=7^2+11^2,
c^2=49+121,
c^2=170,
c=sqrt(170),
c=13.03840481)}}}  

Answer: 13.03840481 rounded off as your teacher wanted, or in simplest radical form:

{{{sqrt(170)}}}

Edwin</pre>