LEARN MATH STEP BY STEP THROUGH VERY EASY PROCESS

GEOMETRY - TYPES OF ANGLES

**TYPES OF ANGLES -**

__Adjacent Angles –__

**Two angles
are called adjacent angles if they have the same vertex and a common arm and
their other arms are on either side of the common arm. In the figure ∠COB and ∠BOA are adjacent angles. ****While ∠COA
and ∠COB
are not adjacent angles.**

__Linear
Pair –__

**Two adjacent angles are said to form a linear pair if the
sum of their measures is 180⁰. Here ∠AOB
& ∠AOC
form a linear pair because 115⁰ + 65⁰ = 180⁰**

__Property
-__ If a ray OA stands on a line BC then the adjacent angles
∠AOB
& ∠AOC
form a linear pair, that is -

**∠AOB
+ ∠AOC
= 180⁰**

**Also, the sum of all the angles at a point of a line on
one side of it is 180⁰. Here ∠BOQ + ∠QOP + ∠POC = 180⁰**

__Complementary
Angles –__

**Two angles are called complementary angles if the sum of their measures
is 90⁰, each angle is said to be the complement of the other. For example, two
angles of measures 32⁰ and 58⁰ are complementary angles.**

__Supplementary
Angles –__

**Two angles are called supplementary angles if the sum of their measures
is 180⁰, each angle is said to be the supplement of the other. For example,
angles of measures 104⁰ and 76⁰ are supplementary angles.**

__Angles
at a Point –__

**The sum of all the angles at a point, making a complete rotation,
is 360⁰. In the figure, 60⁰ + 90⁰ + 90⁰ + 120⁰ = 360⁰**

__Vertically Opposite Angles -__

**When two straight lines AB
& CD intersect at the point 0 then the pairs (1) ∠AOD
and ∠COB
and (2) ∠AOC and ∠BOD
are called vertically
opposite angles.**

** Property** -

**In the figure, ∠AOD = ∠COB
and ∠AOC
= ∠BOD**