# Laurianne

Most popular questions and responses by Laurianne-
## Trigonometry

When using the Law of Cosines, how do I know if two triangles exist?

*asked on January 19, 2010* -
## Trigonometry

Am I doing something wrong? I have to use the Law of Consines with the following numbers: a=30, b=15, c=17. I tried to find the angle a, since a is the longest side. Cos A=(15^2+17^2-30^2)/(2x17x15)=-.7568 The inverse being 139 degrees. But when I multiply

*asked on January 19, 2010*