In Geometry angles are classified on the basis of measurement
Types of angles as per measurements are:
(1) Acute Angle
(2) Right Angle
(3) Obtuse Angle
(4) Straight Angle
(5) Reflex Angle
(6) Full Rotation
Below diagram gives you an idea of different angle types.
Different Angle Types
Given below is the description and properties of different types of Angles in Geometry
Acute Angle
Angle with less than 90 degree of measurement is called Acute Angle
Some examples of Acute angle are:
You can see in the above diagram, all the angles are below 90 degree:
Angle ROA = 30 degree
Angle ROB = 45 degree
Angle ROC = 75 degree
Hence, all these angles are acute angle.
Some other examples of Acute Angles are given below:
Right Angle
Angle forming 90 degree is a right angle
Examples of Right Angle
Obtuse Angle
Angle with greater than 90 degree but less than 180 degree of measurement is Obtuse Angle
Examples of Obtuse Angle
In the above diagram, all the angles are obtuse angle:
Angle ROA = 120 degree
Angle ROB = 135 degree
Angle ROC = 155 degree
All the angles are above 90 degree but less than 180 degree.
Some other examples of obtuse angles are:
Straight Angle
Angle forming exactly 180 degree is straight angle
Reflex Angle
Angle greater than 180 degree but less than 360 degree is reflex angle
You can see that all angles are between 180 and 360 degree
Angle A = 210 degree
Angle b = 260 degree
Angle C = 315 degree
Full Rotation
Angle forming exactly 360 degree is full rotation
Types of Angle – Questions
I hope you have understood the properties of different angles.
Let us put your learning to test.
Below are the collection of questions where you have to identify the type of angle and select the right answer.
(01) Find the angle type for angle A & B
You can observe that:
Angle A = 330 degree
Angle B = 30 degree
Hence Angle A is reflex angle and Angle B is Acute angle
(02) Find the angle type for C & D given in below picture
Angle C = 300 degree (reflex angle)
Angle D = 60 degree (acute angle)
Hence angle C is reflex angle and angle D is acute angle
(03) Find angle type for angle A & B
You can see that:
Angle A = 90 degree (right angle)
Angle B = 120 degree (Obtuse angle)
Hence Angle A is right angle and Angle B is Obtuse angle
(04) Find the angle type for C & D
You can observe that:
Angle C = 135 degree (Obtuse Angle)
Angle D = 45 Degree (Acute Angle)
Hence angle C is Obtuse and D is Acute angle
(05) Find the angle type for given angle A & B
You can see that:
Angle A = 180 degree (Straight angle)
Angle B = 100 degree (Obtuse Angle)
Hence angle A is Straight angle and angle B is Obtuse angle