Geo-Trig question
 

I loved geo-trig in highschool .... but that was a l o n g time ago. :)

I need to know the length of the other two sides of the red triangle. (one side is a known- 20m)

If it is hard to read the angles:

35º48'
54º12'
90º

thanks !!

http://forums.pelicanparts.com/uploa...1322246993.jpg

since you've got all of the angles and one side, there are several ways to do it, but the first one that comes to mind

Tangent of an angle = opposite side length over the adjacent side length.

Then, once you have 2 sides, use the pythagorean theorem to find the third side

c^2=a^2+b^2

I'd try the math, but I'm not sure if you have the triangle drawn wrong but labeled correctly, or if it's drawn correctly and labeled wrong. Based on the drawing, you have the 35° and 54° backwards.

You're right masraum, I have the 54º and the 36º mixed up on the diagram.

If the 35° is supposed to be at the bottom of the triangle which is how it looks, then

Tangent of 35°48' = X/20

therefore

< wrong answer >X = 20 times .72 = 14.42 meters

400 - 208.06 = y^2

y = 13.85 meters < /wrong answer >

I've got to stop trying to work and surf at the same time.

Yeah, instead of pretending that 20 is the hypotenuse...

20^2 + 14.42^2 = C^2 --> C = 24.66

revised diagram:

http://forums.pelicanparts.com/uploa...1322249249.jpg

I cheated. . . but here you go. . .

http://forums.pelicanparts.com/uploa...1322250363.jpg

Here's some info for the smarter guys w/out CAD software. . .

http://forums.pelicanparts.com/uploa...1322250859.jpg

Masraum, since 'y' is the hypotenuse, it's value would have to be greater than the known side of 20m, right??

Tom in Idaho, thank you very much !!


max

Sorry - left out the important stuff. . . (from here: Trigonometry - Wikipedia, the free encyclopedia)

http://forums.pelicanparts.com/uploa...1322251127.jpg

http://forums.pelicanparts.com/uploa...1322251162.jpg

http://forums.pelicanparts.com/uploa...1322251139.jpg

Duh, sorry, was trying to work and surf PPOT at the same time, yeah, forgot I was working with a and b trying to find c.