This past week we finished up Chapter 9. Chapter 9 has been the easiest so far for me. In 9-3 we did Law of Sines and in 9-4 we did Law of Cosines.

LAW OF COSINES:
the formula: (opposite leg)^2=(adjacent leg)^2+(adjacent leg)^2-2(adjacent leg)(adjacent leg)cosine(angle between)
Lets say two sides of a triangle have lengths of 6cm and 12cm and the angle between is 60 degrees. What is the third side?
A)first you must draw your triangle and label it!
B) since we already know our 2 angles and the angle between, we can plug it into the formula.
x^2=6^2+12^2-2(6)(12)cos60 degrees.
C) everything is squared so when you plug it all into your calculator you must square root all of it.
D) your answer is 10.392

This upcoming week will pretty much be an exam review. I feel pretty confident with all these sections so far.