All About Angles
This page talks about the four types of angles: straight, right, obtuse, and acute. It also talks about measuring angles with a protractor and distinguishing between triangles based on the three types of angles.
The four types of angles:
Straight angle: An angle that makes a straight line and measures exactly 180 degrees. Right angle: An angle that measures exactly 90 degrees and is usually indicated with a "right angle box". Acute angle: An angle that measures less than 90 degrees. Obtuse angle: An angle that measures greater than 90 degrees. 
Three types of triangles:
Right Triangle: Has one right angle in it Acute Triangle: Has all acute angles in it Obtuse Triangle: Has one obtuse angle in it Obtuse Triangle:

Practice Problems:
Angles:
Reading Protractors:

Classifying Triangles:
