In week 17 we finished last chapter.This chapter about Trigonometry.It was easy chapter.and we have test about this chapter on Wednesday.

example:  a²=b²+c² we just apdate to r²=x²+y² .This is a firs lesson 

The second lesson about reference angles.The reference angle for any angle in standard position can be determined .for an angle in Quadrant 2 such as 155°,the reference angle is:

180º-155°=25°

The fours lesson about sine law

And some example:

And in the last lesson in this chapter we learned the coding law.

The coding Low :ΔASL    a²=s²+l²-2sl cosA