Rationalizing a Denominator

Ok these are talking about 30-60-90 and 45-45-90 triangles. Also could someone show me what you do for a 30-60-90 and what you do for a 45-45-90 triangle.

Use your new 30-60-90 and 45-45-90 triangle patterns to quickly find the lengths of the missing sides in each of the triangles below. Do not use a calculator. Leave answers in exact form. Note: The triangle are not necessarily drawn to scale. Could someone please show how to solve these I don't have a clue how to do it I have a math test coming up.http://i4.photobucket.com/albums/y109/mal1cous/trig.jpg