Originally Posted by

**ebaines** For the first problem you've left out some critical data - such as the speed of the two boats - so it's impossible to answer as written.

For the 2nd you know that the 3 sides of the triangle are lengths 7, 8, and 9 - do you see what that is? Now apply the law of cosines:

$\displaystyle C^2 = A^2 + B^2 - 2AB \cos(c)$

You have values for A, B and C, so solve for $\displaystyle \cos(c) $ and hence the angle 'c'. Repeat for angle 'b', and angle 'a' is 180 degrees - c - b.