True.
An obtuse triangle has an angle of more than 90 degrees but less than 180 degrees (of course a triangle can never have an angle that is equal or greater than 180 degrees).
An obtuse triangle can be a scalene or an isosceles, but never an equilateral triangle.
(Please draw the polygon such as triangle so you can answer similar problems. I assure you, it will help you solve simple geometry problems.)