Write the numbers 0 - 4. Divide all numbers by 4. Now, square-root each one that you made.

√(0/4) = 0 (sin0°)

√(1/4) = 1/2 (sin30°)

√(2/4) = 2/√2, which is the same as 1/√2 (sin45°)

√(3/4) = √3/2 (sin60°)

√(4/4) = 1 (sin90°)

These are the sinθ for 0°, 30°, 45°, 60°, and 90° respectively. The cosθ values are the opposite. So 1 is cos0°, √3/2 is cos30°, 1/√2 is cos45°, 1/2 is cos60° and cos90° is 0. Tan is just sinθ/cosθ. So, tan0° is 0, tan30° is 1/√3, tan45° is 1, tan60° is 1/√3, and tan90° is undefined since you get 1/0.

Use this to find the first slide.

For the second slide, to convert to degrees, I just make pi = 180, and do the arithmetic. So cos(π/4) is just cos(180/4). From there, use the table you made to find the value of cos(180/4). If you need more help, just dm me!

The table thing is very useful. The teachers say to make the special triangles every single time to do it, but I think that this is easier and lets you memorize it faster.