Sunday, April 22, 2012

Triangles

9-1

SOHCAHTOA


sin theta = opposite/ hypotenuse
cos theta = adjacent/ hypotenuse
tan theta = opposite/ adjacent

-only used an right triangle
-you can't use the 90 degree angle
-an angle of elevation is pointed towards the left
-angle of depression is pointed up

EXAMPLE 1

Edward spots a tree out of a second story window at an angle of elevation of 45 degrees. The second story is 15 feet above ground. How tall is the tree if Edward is 30 meters from the tree.

It is a right triangle.

Tan45= x/30
=30

30+15
= 45 meters

Step1) Draw out your triangle
Step2) Label given angles and sides
Step3)Figure out which part of SOHCAHTOA you are going to have to use. (In this case it was tangent)
Step4) Plug your angle of inclination and your given leg into the formula
Step5) Cross multiply and divide
Step6) Add 15 to the answer you get from using SOCAHTOA to get your final answer


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