Author: cameronc

Remember that an angle is made up of
two arms and a vertex (corner).
You can name an angle using
three capital letters.
The vertex must always be
the middle letter.

B

vertex

arm

A

C

arm

BAC is a short way of saying angle BAC

Reflex Angles

Angles that are bigger than 180° are
called reflex angles. Angles that form
A complete revolution add up to 360°.
Example: ABC forms a
complete revolution with
reflex ABC.
360° - 35° = 325°
So, reflex ABC = 325°

A

B

35°

C

Supplementary Angles

Angles that form a straight line are
called supplementary angles.
Supplementary angles
add up to 180°
Example: ABD forms a
straight line with DBC.
180° - 145° = 35°
So, DBC = 35°

D

A

145°

?°

C

B

35° is said to be the supplement of 145°

Corresponding Angles

Corresponding angles are created where a transversal (A line that cuts across two or more (usually parallel) lines) crosses other lines.
The corresponding angles are the ones at the same location at each intersection (The point where two lines meet or cross).
Corresponding angles have the same degree measurement
Example:
A and C = corresponding angles.
B and D = corresponding angles.

C

D

A

B

Complementary Angles

A

D

Angles that form a right angle are
called complementary angles.
Complementary angles
add up to 90°
Example: ABD forms a
right angle with DBC.
90° - 55° = 35°
So, DBC = 35°

55°

?°

B

C

arm

35° is said to be the complement of 55°

Vertical Angles

Vertical angles are the angles that are opposite each other when two lines intersect .
Vertical angles have the same degree measurement.
Example:
AEB and DEC = vertical angles
BEC and AED = vertical angles

B

A

E

C

D