**Related Angles
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Lines AB and CD are parallel to one another (hence the »
on the lines).

a and d are **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.

© Matthew Pinkney