Trigonometry Triangle Help: Finding Unknown Angles and Sides

[blueparukia]

First off, I was just moved up a grade (about 2 week ago) and the class is studying trigonometry.

Homework Statement

I have a triangle:
Hyp = 10m
Opp = 4m
Adj= Unknown
Feta = Unknown

And I need to find feta.

Homework Equations

?

The Attempt at a Solution

Well, I have tried a lot of random things lol.
E.g: sin-1 (10x4)

Well, that's actually about it.


I also have another question. Exactly from the revision sheet.
By using a radar beam. an observer at A determinses that a plane at B is 2000 metres away (AB=2000) Use the information given to calculate the height of the plane above the horizontal $$\overline AC$$ The angle is 50 degrees. I know the answer is 2000xsin 50, but how do I know t is sin? The teacher gave me the answer, but I don't know how she came up with sin :(


Please help,

BP

 

[HallsofIvy]

In order to do that, you first need to know the definitions of sine, cosine, etc!

sine is defined, in a triangle,as "opposite/hypotenuse", NOT "opposite times hypotenuse. You need to find sin^-1(4/10).

 

[blueparukia]

4/10 thank you! I was using 4x10. Completely forgot.

Thankl you,

BP