Friday, September 24, 2010

9-1 Solving Right Triangles

In advance math this week we learned about right triangles. In 9-1 we learned how to solve right triangles and how to identify all the sides of a triangle. The term we learned in 9-1 dealing with right triangle and how to solve. It is called SOHCAHTOA.

SOHCAHTOA stands for:
-Sin theta= opp/hyp
-Csc theta= hyp/opp
-Cos theta= adj/hyp
-Sec theta= hyp/adj
-Tan theta= opp/adj
-Cot theta= adj/opp



All those function which is known as SOHCAHTOA is only used with right triangles. Another thing is the hypotenuse is opposite of the right angle.


In chapter 7, we defined the trigonometric functions in terms of coordinates of points on a circle. In this chapter, our emphasis shifts from circles to triangles. When sides and angles of a triangle are known, you will see that trigonometry relationships can be used to find the unknown parts. This is called solving a triangle. For example, if you know the lengths of the sides of a triangle, then you can find the measures of its angles. This lesson is basically explaining how trigonometry can be applied to right triangles.



Examples of solving a right triangle:

For triangle ABC
Solve the triangle
- they give you
Angle C=90degrees
Angle A=28degrees
A=40
- you are looking for
Angle B
C
B
- finding C you do Sin 28degrees=40/c.
- multiply c on both side you get c sin 28degrees= 40.
- you divide sin 28degrees over.
- you get c=40/sin 28degrees.
- the answer you get is 85.202 which is C.
- Finding B you do Tan 28degrees=40/b.
- multiply b over you get b tan 28degrees=40.
- you divide tan 28degrees over.
- you get b=40/tan 28degrees.
- the answer you get is 75.229 which is B.
- Finding angle B
you do 180-90-28.
- you get 62 degrees.
- you solve the whole triangle and you are done.



Basically if you know all your steps and formula and SOHCAHTOA . Lesson 9-1 is really easy and not hard but just takes time and be careful and know what is your hypotenuse because you can messed up your whole problem if you do not know which one is the hypotenuse but other than that 9-1 is easy and you would not have any trouble at all if you know SOHCAHTOA.

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