Sunday, September 26, 2010

This week we finished chapter 8 and started learning chapter 9. Chapter 9 takes us back to what we learned in geometry.

SOHCAHTOA
sin=opposite/hypotenuse
cos=adjacent/hypotenuse
tan=opposite/adjacent
csc=hypotenuse/opposite
sec=hypotenuse/adjacent
cot-adjacent/opposite

For most problems you will either use sin, cos, or tan.

Example:
for triangle ABC
A=90 degrees B=24 degrees a=36

Since we already have angles A and B we need to find C.
1) first subtract 90 degrees and 24 degrees from 180 degrees.
your answer is 66 degrees.
2) in order to find angles b and c you need to use angle B to solve. To solve for b you can use sin-opp/hyp. Sin 24 degrees=b/36.
3) 36sin24 degrees=14.643.
4) to find c you need to use cos=adj/hyp.
cos24 degrees=c/36
5) 36cos24 degrees=32.888

Since we have everything worked out your answers are:
A=90 degrees
B=24 degrees
C=66 degrees
a=36
b=14.643
c=32.888

At first I was completely lost until I sat down and worked a few problems. I somewhat remembered SOHCAHTOA from geometry and its very easy when working these problems.

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