how do you know when to use sine law or cosine.

- jaybird0827
**Posts:**22**Joined:**Tue May 26, 2009 6:31 pm**Location:**NC-
**Contact:**

frankie10 wrote:how do you know when to use sine law or cosine.

See next post below ...

Last edited by jaybird0827 on Wed Jun 17, 2009 10:12 pm, edited 2 times in total.

- stapel_eliz
**Posts:**1686**Joined:**Mon Dec 08, 2008 4:22 pm-
**Contact:**

frankie10 wrote:how do you know when to use sine law or cosine.

If you have two angles and a side opposite one of them, or two sides and an angle opposite one of them, then use the Law of Sines, because you have the information that fits.

If you have two sides and the included angle, or all three sides and need an angle, use the Law of Cosines, because you have the information that fits.