CAT Various Types of Angle - Practice Questions & MCQ

The measure of an angle is the amount of rotation from the initial side to the terminal side. Probably the most familiar unit of angle measurement is the degree. An angle measured in degrees should always include the unit “degrees” after the number, or include the degree symbol '°'. For example, 90 degrees=90°.

Various Types of Angles 

Acute Angle: An angle whose measure is more than 0° but less than 90° is called an acute angle. 

Right Angle: An angle whose measure is equal to 90° is called a right angle. 

Obtuse Angle: An angle whose measure is more than 90° but less than 180° is called an obtuse angle. 

Straight Angle: An angle whose measure is equal to 180° is called a straight angle. 

Reflex Angle: An angle whose measure is more than 180° but less than 360° is called a reflex angle.

Complete Angle: An angle whose measure is equal to 360° is called a complete angle. 

Complementary Angles: When the sum of the measures of two angles is 90°, such angles are called complementary angles. Two complementary angles are called the complement of each other 

For example, An angle of 30° and another angle of 60° are complementary angles of each other. 

Also, complement of 30° is 90° - 30° = 60°.

And complement of 60° is 90° - 60° = 30°

Supplementary Angles: When the sum of the measures of two angles is 180°, such angles are called supplementary angles. Two supplementary angles are called the supplement of each other

For example, An angle of 120° and another angle of 60° are supplementary angles of each other.

Also, supplement of 120° is 180° - 120° = 60°.

And supplement of 60° is 180° - 60° = 120°

Adjacent Angle: Two angles are adjacent, if they have a common vertex, a common arm and their non-common arms are on different sides of the common arm.

In the given figure above, ∠AOC and ∠BOC are adjacent angles having the same vertex O, a common arm OC and their non-common arms OA and OB on either side of OC. 

Moreover, when two angles are adjacent, then their sum is always equal to the angle formed by the two non-common arms. So, we can write:

∠AOB = ∠AOC + ∠BOC