Triangle ptg has side lengths of 18 27 cm and 13 cm what type of triangle is it

Angle PTG = arccos ((18^2 + 13^2 - 27^2) / (2 x 18 x 13)) = arccos (-236 / 468) = arccos (-0.5043) = 120 degrees.

The triangle is an obtuse triangle (because one of the angles is greater than 90 degrees) and a scalene triangle (because all the sides are not equal).