In the above drawing, each of the tic-marks are equal and
represent 1 inch each. The angle B has measure 45°. We can
see by the arc that the line AC, which equals 3 inches, is
not long enough to reach the slanted side of the 45° angle.
Therefore triangle ABC is not possible. We can also show
by the law of sines that no triangle ABC with the given
properties in possible.
Since sines of angles are always less than one, this shows
that there is no possible way to have an angle C. Therefore
it is impossible to have a triangle ABC with the given
properties.
Edwin