# Trigonometry with Vectors

• C42711

#### C42711

[PLAIN]http://img832.imageshack.us/img832/449/physicsu.png [Broken]
By c42711 at 2011-10-30

I am supposed to find the X and Y components of the above vector. What I tried to do first was dot in a line, forming a triangle. I then tried to find the length of that line using tangent. I got 431.8, but I am not sure that is right. Next, I used the Pythagorean theorem to try to find the X and Y components, I got some crazy numbers, so I know I'm doing something wrong. Any help would be fantastic. Please & thank you.:)

Last edited by a moderator:
Tangent is not the correct function to use. 147km is the hypotenuse of the triangle.

You'd need to use sine for the vertical and cosine for the horizontal. The sine of the angle is y / the hypotenuse, so y = sin71.2 * h. Similarly, x = cos71.2 * h. Hope that helps.

So I tried that and got:
Fx= 47.4 km
Fy= 139 km

Does that seem correct?

Yeah, those are the correct values.

Than you so much, you're the best.:)