A right triangle has one 90 degree angle and two angles less than 90 degrees. An acute triangle has all angles measuring less than 90 degrees. An obtuse triangle contains one angle over 90 degrees and the other two angles are less than 90 degrees.

1. 90
A right triangle always has
a 90 degree angle and two
angles that are less than
90 degrees.
All angles in an acute
triangle are less than 90
degrees.
An obtuse triangle has one
angle over 90 degrees and
two angles that are less
than 90 degrees.