Creating a Unit Circle Part 3 of 4

Creating a Unit Circle Part 3 of 4 - SOH-CAH-TOA

SOH-CAH-TOA

You must memorize for the rest of your life this nonsense phrase SOH-CAH-TOA (said "so" "KAH" "TOE-ah" Note: I teach math, not English, so give the pronunciation your best)

If you are wise, from this point onward in your Trigonometry career you will write SOH-CAH-TOA at the top of every worksheet, test, and scratch paper until it has become a part of you.

Here is what it stands for:

For the purposes of this lesson, we're just reviewing this information and we're not going to go too far in depth.

Which Side is Which?

It all has to do with how the side is placed relative to 𝚹 (Theta, we use Greek symbols to be variables for angle measurements). The Leg that is attached to or "Adjacent" to 𝚹 is the "Adjacent" side. The side not touching 𝚹 at all or the side that is "Opposite" 𝚹 is the "Opposite" side. the Hypotenuse is still the Hypotenuse, as always.

So, sin(𝚹) = the measurement of the side opposite to 𝚹 divided by the measurement of the hypotenuse

cos(𝚹) = the measurement of the side adjacent to 𝚹 divided by the measurement of the hypotenuse

Here's an example using the 30-60-90 triangle:

Practice Finding the Sin and Cos of Right Triangles

Remember that you can't leave a radical in the denominator!

Here is a worksheet with answers at the bottom to help you practice.

I also found this worksheet for more practice problems with the answers attached at the bottom.

I Still Need More Help!

Check out the Math is Fun Website's explanation

Here is a Khan Academy article that you might find useful

Watch this video to see Nancy, our Math BFF, walk through Trig Ratios

What Should I Have Filled Out In My Notes?

You should now be able to fill out the rest of the table with all of the answers for the sine and cosine of all of the angles in the table on your notes page.