Common Greek Symbos: alpha – α, beta – β, gamma – γ, thita – θ
Negative angles and measurements in radians will not be considered at this level.
Angles are classified based on the the fraction of a complete turn about a point. Full circle is 360°.
Revolution

Straight Angle

Right Angle

Acute Angle

Obtuse Angle

Reflex Angle

More than one revolution will result in addition of 360° 
Pair of Angles
Angles are classified based on the the fraction of a complete turn about a point. Full circle is 360°. 

Supplementary Angles
Two angles which add to 180° are called supplementary angles. These angles may not be adjacent angles. 
Complementary Angles
A pair of angles which add to 90° are called complementary angles. These angles may not be adjacent angles. 
Linear Pair A linear pair is a pair of adjacent angles formed when two lines intersect.
p+q=180° 

Lines which meet at 90° are called perpendicular lines 