No two sides are equal, so the triangle is not an isosceles triangle.
We could calculate at least two angles of the triangle to determine whether it is a right, acute, or obtuse. We need to use the cosine law:
a^2 + b^2 - 2ab * cos C = c^2
cos C = (a^2 + b^2 - c^2) / 2ab
C = arccos((a^2 + b^2 - c^2) / 2ab)
Solving for two angles P and T,
P = arccos((12^2 + 19^2 - 25^2)/(2*12*19))
P = 105.3 degrees.
Since one angle is an obtuse angle, we dont need to compute for the other angle. We can conclude then that the triangle is an obtuse angle.