# Rationalizing a Denominator

• Dec 13th 2007, 06:48 PM
peachgal
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
• Dec 14th 2007, 08:44 AM
topsquark
Quote:

Originally Posted by peachgal
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

What does this have to do with rationalizing a denominator??

For a), you know that the top angle is 60 degrees because the bottom one is 30. You also know that the side adjacent to the 60 degree angle is 10. So the hypotenuse is twice that, 20. And the side across from the 60 degree angle is $\displaystyle 10\sqrt{3}$ by the Pythagorean theorem.

For b), you know that the bottom angle is 45 because the top angle is 45. You know that one leg is 4, so the other leg is 4. You also know that the hypotenuse is $\displaystyle 4\sqrt{2}$ by the Pythagorean theorem.

-Dan