Angles and Lines  
Summary 
an angle is formed when two lines intersect at a point called the vertex. angles are usually measured in degrees ( ^{o} ) and minutes ( ' ). all angles can be classified according to their size. e.g. acute angles, right angles etc. properties of angles include angles on a straight line, angles at a point and vertically opposite angles. 
Key Skills 

Vocabulary 
angle, vertex, degree, minute, complementary, supplementary, adjacent, acute, right angle, obtuse angle, reflex angle, congruent, vertically opposite 