To find if the triangle is acute (angles with a measure less than 90º), right (an angle of 90º) or obtuse (one angle with measure more than 90º) you find the sum of the two smaller sides squared:
If that sum is less than the largest side squared it is a acute triangle
If that sum is grather than the largest side squared it is a obtuse triangle
If that sum is equal to the largest side squared is a right triangle
The smaller sides in the given triangle are 65 and 72:
Sum of smaller sides squared:
Largest side squared:
As 9409=9409, It is a right triangle