Which angle measures less than 90 degrees but more than 0 degrees?

An angle that measures less than 90 degrees but more than 0 degrees is known as an acute angle. Acute angles are defined specifically as angles that fall within this range, making them the only option among the choices provided that fits this criterion.

Right angles are characterized by their measurement of exactly 90 degrees. Straight angles are equal to 180 degrees, representing a straight line. Obtuse angles are larger than 90 degrees but less than 180 degrees. Therefore, none of these options can be classified as less than 90 degrees and more than 0 degrees.

In summary, the correct choice, an acute angle, is the only angle that measures less than 90 degrees and more than 0 degrees, thus fulfilling the requirements of the question.