alright.. Here if Mr. Magic Ford...
As you should know, you can only use SOH CAH TOA (sin, cos,tan) with a special right triangle.
A trick i learned that is quite helpful when you dont know which of the three to use is;
SOH: Sin=Opposite/Adjacent angles.
CAH: Cos= Agjacent/Hypotenuse
TOA: Tan= Opposite/Adjacent
~~~~~~~~~~~~~~~~~~~~~~
It is very easy to remember. When you have your test, just write SOH CAH TOA on the top and it will be very helpful.
Now, you should know which angle is which.. For instance.. In you example you have
the ladder.
Well. If you get out your handy dandy notebook.. Just draw a Right angle triangle. Make the right angle the bottom left angle. Just draw a box in the angle. Now, you should have the tallest part of the triangle unlabled. (not the slanted part), the for the bottom leg of the triangle draw it out a little and put a 10 under it. then for the angle of elevation with the ground. For the angle that is also on the bottom you should label it 40
Now, you should have 2 angles marked. one with the box (90) and one labeled 40. Then you should have only one side labeled. (10) so you should have one open angle, and two open sides..
Well, if you know from experience, in a triangle, all sides must add up to 180 degrees. You already have the one angle at 90, so that is half. So if you wanted to, you could find the empty angle for whatever reason. just use simple math.. 40+50=90 ~> 90+90 =180.
Now you know the third angle. This can be helpful for checking to make sure your answer is right later on.
Now, all you need to do is find the height of the wall. (H). Well in this case, you could use TANJIT. So when you hit the TAN button on your calculator it comes up with ~> tan( <~ right after the ( is where you put the angle you have.
Tan could be used in either the 50 degree angle, or the 40 degree. I would use the 40 because that was givin, so you know it is right.
So, if you follow SOH CAH TOA, you will see for TOA it is tan= opposite over adjacent. Meaning... your equation would look as follows for this problem :
tan(40 H
------- = -------
~ 10
in this case you see the H is DIVIDED by 10. to make the problem easier, you just move the equation..
10tan(40=h
What i did was move the dominator in the problem to the top, making it all one easy step.
if you put it in your calculator just like that, it will give you the correct answer..
H= 8.290996312ft.
Any more questions just ask..
BFM_»FØRЫ