Access free live classes and tests on the app
Download
+
Unacademy
  • Goals
    • AFCAT
    • AP EAMCET
    • Bank Exam
    • BPSC
    • CA Foundation
    • CAPF
    • CAT
    • CBSE Class 11
    • CBSE Class 12
    • CDS
    • CLAT
    • CSIR UGC
    • GATE
    • IIT JAM
    • JEE
    • Karnataka CET
    • Karnataka PSC
    • Kerala PSC
    • MHT CET
    • MPPSC
    • NDA
    • NEET PG
    • NEET UG
    • NTA UGC
    • Railway Exam
    • SSC
    • TS EAMCET
    • UPSC
    • WBPSC
    • CFA
Login Join for Free
avtar
  • ProfileProfile
  • Settings Settings
  • Refer your friendsRefer your friends
  • Sign outSign out
  • Terms & conditions
  • •
  • Privacy policy
  • About
  • •
  • Careers
  • •
  • Blog

© 2023 Sorting Hat Technologies Pvt Ltd

  • CAT 2023
  • Study Materials
  • Notifications
  • CAT Syllabus
  • CAT Mock Test
  • CAT Exam Pattern
  • CAT Question Paper
  • CAT Preparation Books
  • Downloads
  • Important Formulas
  • Eligibility Criteria
CAT 2025 » CAT Study Material » Quantitative Ability (Mathematics) » Complementary Angles
scholarship_cat

Complementary Angles

When it comes to geometry, complementary angles are defined as two angles that add up to 90 degrees. In other terms, complementary angles are defined as two angles that sum up to 90 degrees when added together. For example, 60° and 30° are both acceptable. In this article, we'll discover more about what it is.

Table of Content
  •  

The sum of the two angles’ measurements determines the complement and supplement of the two angles’ measurements. This is referred to as a complementary angle pair when the sum of the two angles is equal to the measurement of the right angle in the pair of angles.

Complementary angles are pairs of angles with a sum of 90 degrees. Always keep in mind that complementary angles occur in pairs when discussing them. One angle is the counterpart of the other. Although a right angle is 90 degrees, it cannot be considered complimentary because it does not occur in pairs. There is only one angle present. Three or more angles whose sum equals 90 degrees cannot be considered complementary angles. Complementary angles have always positive measurements. It consists of two acute angles measuring less than 90 degrees.

What is the complementary angle?

The sum of two angles is considered to be complementary if the sum of the angles equals 90 degrees. To put it another way, when two complementary angles are combined, they make a right angle (see figure) (90 degrees). A pair of angles 1 and 2 are complementary if the sum of their respective angles is equal to 90 degrees (that is, if angle 1 plus angle 2 equals 90°). As a result, angle 1 and angle 2 are referred to as complements of each other.

In the illustration below, 60° plus 30° equals 90°. Following the “Definition of Complementary Angles,” it may be concluded that these two angles are complementary. Each of the complementary angles is referred to as the “complement” of the other angle in the pair. Here,

The angle 60° is the complement of the angle 30°.

30° is complimentary to 60°.

Adjacent complementary angles 

When the total of two angles is equal to the measurement of a right angle, the pair of angles is referred to as the complementary angle (or the complementary triangle). Complementary angles in geometry are classified into two categories, which are as follows:

Angles that are adjacent and complementary to one another

Complementary Angles that are not contiguous to one another

Angles that are adjacent and complementary: The term “adjacent complementary angles” refers to two complementary angles that share a shared vertex and a common arm. In the illustration below, the angles COB and AOB are neighbouring angles because they share a common vertex (“O”) and a shared arm (“OB”) The angles COB and AOB add up to 90 degrees, as shown by the equation COB + AOB = 70°+20° = 90°. As a result, these two angles are complementary angles that are next to one another.

Non-adjacent complementary angles 

Non-adjacent Complementary Angles: Two complementary angles that are NOT next to one another are referred to as non-adjacent complementary angles in mathematics. In the diagram below, the angles ABC and PQR are not neighbouring since they do not share a common vertex or a common arm. Further to this, they sum up to 90 degrees, as in AB+ PQR = 50°+ 40° =90°. As a result, these two angles are complementary angles that are not contiguous. In the case of non-adjacent complementary angles that are not neighbouring, they combine to form a right angle.

Important points 

Complementary angles are defined as those in which the sum of the two angles equals or exceeds 90 degrees. When two angles are 50 degrees and 40 degrees apart, these angles are complementary since the sum of these angles is 90 degrees: 50 + 40 = 100 ° angle of complementarity.

When two angles are complementary to each other, angle one is referred to as the complement of angle 2, and angle two is referred to as the complement of angle one.

It makes no difference where the angles are located. The only requirement for a pair of angles to be considered complimentary is that the total of their respective angles should be 90 degrees.

It is possible for two sharp angles to be complementary.

It is impossible for two obtuse to be complementary.

It is impossible for one obtuse angle and one acute angle to be complimentary.

Because one right angle is equal to 90 degrees, two right angles cannot be complementary to each other.

Properties of complementary angles 

When the sum of two angles equals 90 degrees, they are said to be complimentary.

They can either be adjacent or non-adjacent to one another.

Even though the sum of three or more angles is 90 degrees, they cannot be considered complementary.

When two angles are complementary to one another, one angle is referred to as the “complement” or “complement angle” of the other.

A right-angled triangle has two acute angles that are complementary to one another.

Conclusion 

Complementary angles are pairs of angles with a sum of 90 degrees. A right angle is 90 degrees but cannot be considered complimentary because it does not occur in pairs. Three or more angles whose sum equals 90 degrees cannot be complementary abundantly. Complementary angles are defined as those in which the sum of the two angles equals or exceeds 90 degrees. They can either be adjacent or non-adjacent to one another. In the diagram below, the angles ABC and PQR are not neighbouring since they do not share a common vertex or a common arm.

faq

Frequently Asked Questions

Get answers to the most common queries related to the CAT Examination Preparation.

Find the compliment angle of 55°?

Solution – let the compliment of 55° be x X° + 55° =90°...Read full

Find the angle that is 46° less than its complement.

Solution – let the missing angle be x  (90-x) – x = 46°...Read full

Determine the angles if the difference between two complementary angles is 18 degrees.

Solution – let the smaller angle be x  And the bigger will be (90-x)...Read full

Find the complement angle of 2/3 of 90 degrees.

Solution- 90° x 2/3 = 60°  90° – 60° = 30° ...Read full

Two complementary angles are such that one of the angles is twice the sum of the other angle plus 3 degrees. Find two complementary angles.

Solution.  Let the two angles be x and y degrees. ...Read full

Solution – let the compliment of 55° be x

X° + 55° =90°

X ° = 90°-55° 

X = 35° 

Hence, the compliment of 55° is 35°.

Solution – let the missing angle be x 

(90-x) – x = 46°

90 – x -x = 46 

90- 2x = 46 

2x = 46-90

-2x = 90-46

-2x = -44

2x = 44 

X = 44/2 

X = 22.

Therefore 90-22 = 68°

Solution – let the smaller angle be x 

And the bigger will be (90-x) 

(90° – x) – x = 18°

90° – 2x = 18°

x = 72°/2

x = 36°

90° – x

= 90° – 36°

= 54°.

Therefore, the two complementary angles are 36° and 54°.

Solution- 90° x 2/3 = 60°

 90° – 60° = 30°

Therefore, the complement angle is 30°

Solution. 

Let the two angles be x and y degrees.

x + y = 90°

One of the angles is twice the sum of the other angle plus 3 degrees.

x = 2(y + 3)

 x = 2y + 6

now solve the equations using the substitution method 

2y + 6 + y = 90

3y + 6 = 90

3y = 84

y = 28

 x = 2(28) + 6

x = 56 + 6

x = 62.

Crack CAT with Unacademy

Get subscription and access unlimited live and recorded courses from India’s best educators

  • Structured syllabus
  • Daily live classes
  • Ask doubts
  • Tests & practice
Learn more

Notifications

Get all the important information related to the CAT Exam including the process of application, important calendar dates, eligibility criteria, exam centers etc.

CAT Eligibility Criteria 2023
CAT Exam Pattern 2023
CAT Result 2022
CAT Syllabus 2023 – CAT Exam Syllabus – Download Latest PDF
IBSAT 2022 Notification
IIFT Notification
MAH CET Notification
MICAT Notification
NMAT Notification
SNAP Notification
TISSNET Notification
Top Colleges in India That Accept CAT Score
XAT Notification
See all

Related articles

Learn more topics related to Quantitative Ability (Mathematics)
Work and Time

The work and time problems relate the concept of work and time to each other when an action is put into effect by an individual or a group of individuals. To get the outcome of these problems, a certain set of formulas are to be used.

What are the Real-Life Uses of a Square

In this article, we will learn about the square, the properties of a square, the common properties of square and rectangle and the formulas of a square.

What are the Arithmetic Concepts in Partnership Accounting

In this article we will study about the Arithmetic Concepts in Partnership Accounting, what is the basic concept of Partnership accounting? What are the concepts of partnership deed? Accounting for Partnership definition and more.

What are Special Parallelograms and their Importance in Mensuration

In this article, we will learn about the parallelogram, it’s properties, special parallelograms such as rhombus, rectangle and square, it’s properties and formulas.

See all
Access more than

469+ courses for CAT – Optional

Get subscription

Trending Topics

  • CAT Mock Test
  • CAT Question Papers
  • CAT 2021 Question Paper
  • CAT 2020 Question Paper
  • CAT Question Paper 2019 PDF
  • Best Books for CAT Preparation
  • CAT Eligibility Criteria
  • CAT Syllabus
  • CAT Exam Pattern
  • CAT Result
combat_cat

Related links

  • Co-ordinate Geometry applications
  • What Is A Polygon?
  • Uses of a Quadrilateral
  • Algebraic Identities
  • SPSS Full Form
  • Geometric Progression’s Uses
  • Blood Relation Questions
freeliveclasses_cat
CAT 2024 Question Paper
.
Company Logo

Unacademy is India’s largest online learning platform. Download our apps to start learning


Starting your preparation?

Call us and we will answer all your questions about learning on Unacademy

Call +91 8585858585

Company
About usShikshodayaCareers
we're hiring
BlogsPrivacy PolicyTerms and Conditions
Help & support
User GuidelinesSite MapRefund PolicyTakedown PolicyGrievance Redressal
Products
Learner appLearner appEducator appEducator appParent appParent app
Popular goals
IIT JEEUPSCSSCCSIR UGC NETNEET UG
Trending exams
GATECATCANTA UGC NETBank Exams
Study material
UPSC Study MaterialNEET UG Study MaterialCA Foundation Study MaterialJEE Study MaterialSSC Study Material

© 2025 Sorting Hat Technologies Pvt Ltd

Unacademy
  • Goals
    • AFCAT
    • AP EAMCET
    • Bank Exam
    • BPSC
    • CA Foundation
    • CAPF
    • CAT
    • CBSE Class 11
    • CBSE Class 12
    • CDS
    • CLAT
    • CSIR UGC
    • GATE
    • IIT JAM
    • JEE
    • Karnataka CET
    • Karnataka PSC
    • Kerala PSC
    • MHT CET
    • MPPSC
    • NDA
    • NEET PG
    • NEET UG
    • NTA UGC
    • Railway Exam
    • SSC
    • TS EAMCET
    • UPSC
    • WBPSC
    • CFA

Share via

COPY