Let's redraw the given figure, to easily understood the problem:
The figure appears to be a triangle with the following given,
c = AB = 17 cm
a = BC = unknown
b = CA = 44 cm
θ = 125°
m∠B means it is the angle at vertex B of the triangle, it is also the only angle given in the figure.
Therefore, the measure of m∠B is 125°.