## Saturday, February 22, 2014

### **ALL THESE TRIANGLES ARE LOCATED IN THE FIRST QUADRANT AND FOUND ON THE WORKSHEET FROM KIRCH**

30* TRIANGLE
We first had to label the triangle according to the rules of Special Right Triangle: the hypotenuse (r) would be 2x, the vertical side (y) would be x, and the horizontal side (x) would be x radical 3. Then in order to get the values of each side we have the simply the sides where the hypotenuse would equal 1. So we divide all the side by 2x. 2x/2x simplifies to 1, the hypotenuse. x/2x, the x's cancel out and leave 1/2. x radical three/2x, the x's cancel out, leaving radical 3/2. Next we drew the coordinate plane with the triangle lying in quadrant 1. Now the origin will be (0,0). The coordinates for 90* angle will be (radical 3/2, 0) since the distance between the origin and the 90* is radical 3/2. The outermost angle (60*) will be (radical 3/2, 1/2) because now we move up y which equals 1/2.

45* TRIANGLE

60* TRIANGLE
Last angle! The hypotenuse (r) is 2x - like the 30* triangle. The vertical side (y) is x radical 3 and the horizontal side (x) is x. Now again we must simplify the sides in order to have the hypotenuse equal 1 so we divide all sides by 2x. (y)'s x radical 3/2x will simplify to radical 2/2 while (x)'s x will simplify to be 1/2, the opposite of 30*. Once again the origin will be (0,0). 90* angle will be (1/2, 0) since x's distance is 1/2 and the last angle will be (1/2, radical 3/2) since y's distance from x is radical 3/2.

This activity was able to help me derive the Unit Circle by providing the angles for the first quadrant of the circle and establishing a foundation for the Unit Circle. Note that the coordinates for the 30*, 45*, 60*, in the first quadrant are the same as the ones I had mentioned previously, and they are also all positive!

As I had mentioned, the triangles lied in the first quadrant, where both x and y are positive (+) The values change if drawn in quadrant 2, 3, or 4 by sign changes meaning the value being positive or negative.

This is the 60* triangle drawn in the 2nd quadrant. Everything is still the same as it was in the 1st quadrant, only now the x value is negative due to the quadrant's location and the knowledge of positive and negative components on a graph. Because x is negative so is the x-coordinate in the 2nd quadrant.

x: negative (-) | y: positive (+)

This is the 45* triangle drawn in the third quadrant. It is still the same as the 45* triangle drawn in the 1st quadrant only flipped and now both x and y are negative (again this is due to basic knowledge of the positive and negative components of a graph)

BOTH (-)

x: negative | y: negative

And lastly, this is the 30* triangle. Once again, it is made of the same components as the triangle in the 1st quadrant only the value of positive and negative changed. This time y is negative due to being located in quadrant 3, meaning that the y coordinate will be -1/2. X will remain positive.

x: positive (+) | y: negative (-)