L would measure at 54°. Because the angels of a triangle measure up to 180, you can set the equation up like this: 5x + 3x + 2x = 180. These are like values, so you can add them together to simplify a bit, yielding 10x = 180. Divide 180 by 10 to get x by itself, giving you 18. L = 3x, so 3(18) = 54.
