Related Angles
Lines AB and CD are parallel to one another (hence the » on
the lines).
a and d are known as vertically opposite angles.
Vertically opposite angles are equal. (b and c, e and h, f and g are also
vertically opposite).
g and c are corresponding angles.
Corresponding angles are equal. (h and d, f and b, e and a are also
corresponding).
d and e are alternate angles. Alternate angles are
equal. (c and f are also alternate). Alternate angles form a 'Z' shape and are
sometimes called 'Z angles'.
a and b are adjacent angles. Adjacent
angles add up to 180 degrees. (d and c, c and a, d and b, f and e, e and g, h
and g, h and f are also adjacent).
d and f are interior angles.
These add up to 180 degrees (e and c are also interior).
Any two angles
that add up to 180 degrees are known as supplementary angles.
The angles around a point add up to 360 degrees. The
angles in a triangle add up to 180 degrees. The angles in a quadrilateral add
up to 360 degrees. The angles in a polygon (a shape with n sides) add up to
180(n  2) degrees. The exterior angles of any polygon add up to 360
degrees.
Copyright © Matthew Pinkney 2003
