Arithmetic
Additive Identity
Arithmetic Progression
Associative Property
Averages
Brackets
Closure Property
Commutative Property
Conversion of Measurement Units
Cube Root
Decimal
Distributivity of Multiplication over Addition
Divisibility Principles
Equality
Exponents
Factors
Fractions
Fundamental Operations
H.C.F / G.C.D
Integers
L.C.M
Multiples
Multiplicative Identity
Multiplicative Inverse
Numbers
Percentages
Profit and Loss
Ratio and Proportion
Simple Interest
Square Root
Unitary Method
Algebra
Cartesian System
Order Relation
Polynomials
Probability
Standard Identities & their applications
Transpose
Geometry
Basic Geometrical Terms
Circle
Curves
Angles
Define Line, Line Segment and Rays
Non-Collinear Points
Parallelogram
Rectangle
Rhombus
Square
Three dimensional object
Trapezium
Triangle
Quadrilateral
Trigonometry
Trigonometry Ratios
Data-Handling
Arithmetic Mean
Frequency Distribution Table
Graphs
Median
Mode
Range

Videos
Solved Problems
Home >> Triangle >> Properties >> Sum of Two Sides >>

Sum of Two Sides of the Triangle is Always Greater than the Third Side

Sum of Two Sides Angle Sum Property Angles opposite to equal sides of triangle are equal Angle opposite to longer side is greater Pythagoras Theorem
Exterior Angle Property of a Triangle Mid point property of Triangle Triangles on same base & between same parallel lines

This Property can be understood from the below two examples :-

Example 1 = Below figure represent Triangle PQR



In the above figure, Triangle PQR has
PQ = 4.5 cm
QR = 8 cm
PR = 6 cm

Now Lets, check the property

PQ + QR > PR
4.5 + 8 > 6
12.5 > 6 ----- (True)

QR + PR > PQ
8 + 6 > 4.5
14 > 4.5 ----- (True)

PR + PQ > QR
6 + 4.5 > 8
10.5 > 8 ----- (True)

Hence, it's proved that "Sum of Two Sides of the Triangle is Always Greater than the Third Side."


Example 2 = Below figure represent Triangle ABC



In the above figure, Triangle ABC has
AB = 4 cm
BC = 5 cm
CA = 6 cm

Now Lets, check the property

AB + BC > CA
4 + 5 > 6
9 > 6 ----- (True)

BC + CA > AB
5 + 6 > 4
11 > 4 ----- (True)

CA + AB > BC
6 + 4 > 5
10 > 5 ----- (True)

Hence, it's proved that "Sum of Two Sides of the Triangle is Always Greater than the Third Side."

Similarly, we can check and prove that "The difference of two sides of a triangle is smaller than the third side "

Study More Solved Questions / Examples

  • Can a triangle be constructed with sides 4 cm, 5 cm & 10 cm ?
  • Can a triangle be formed with sides 6 cm, 7 cm & 3 cm ?
  • In the following diagram, ABC is triangle and D is a point on side BC:

  • In the following quadrilateral:



    Prove: PQ + QR + PS + RS > PR + QS
  • Lengths of two sides of a triangle are 7 cm and 9 cm. Can you guess between which two numbers will the length of third side fall ?
  • Copyright@2022 Algebraden.com (Math, Algebra & Geometry tutorials for school and home education)