Here are the steps to follow:

Draw a right triangle. Label an angle q:




Since , label the
side adjacent to q as the numerator of , which is 2, and
label the hypotenuse as the denominator of , which is 3.




Use the Pythagorean theorem to find the third side which is the
side opposite to q. Label the side opposite to q as what you get. 
(It will be a square root.)

Then use the fact that  to get the answer.  
Be sure to rationalize the denominator.

Edwin