Perimeter of a Triangle
We will discuss here how to find the perimeter of a triangle. We know perimeter of a triangle is the total length (distance) of the boundary of a triangle.
Perimeter of a triangle is the sum of lengths of its three sides.
For example, perimeter of the ∆PQR = PQ + QR + RP
● The perimeter of a triangle ABC
= AB + BC + CA
= 2 cm + 4 cm + 3 cm,
(add the length of each side of the triangle).
= 9 cm
Perimeter of the triangle = Sum of the sides.
● A triangle has 3 sides
The perimeter of the triangle XYZ
= 3 cm + 5 cm + 4 cm
= 12 cm
The perimeter of the triangle = Sum of the lengths of three sides.
Let us consider some of the examples on perimeter of a triangle:
1. Find the perimeter of a triangle having sides 3 cm, 8 cm and 6 cm.
Solution:
Perimeter of a triangle
= Sum of all the three sides
= AB + BC + AC
= 3 cm + 8 cm + 6 cm
= 17 cm
2. Find the perimeter of the triangle PQR whose sides are 4 cm, 6 cm and 8 cm.
Solution:
In the figure PQ = 4 cm, PR = 6 cm and QR = 8 cm
The perimeter of the rectangle PQR
= 4 cm + 6 cm + 8 cm
= 18 cm
3. Find the perimeter of an equilateral triangle whose one side is 5 cm.
Solution:
A triangle in which all the sides are equal is called an equilateral triangle.
Perimeter of the equilateral triangle = 3 × side
= 3 × 5 cm
= 15 cm
Thus, perimeter = 15 cm.
4. Find the perimeter of a triangle whose length of three sides are 8 cm, 11 cm, 13 cm.
Solution:
To find the perimeter of the triangle, we add all the sides together.
Perimeter of a triangle
= Sum of all the three sides
= 8 cm + 11 cm + 13 cm
= 32 cm
5. Find the perimeter of a triangle whose sides are 5 cm, 2 cm and 3 cm.
Solution:
Perimeter of the triangle is the sum of the lengths of its sides.
Perimeter = 5 cm + 2 cm + 3 cm
Thus, perimeter = 10 cm.
6. Find the perimeter of each triangle.
Solution:
(i) Perimeter of ∆XYZ = 5.5 cm + 6 cm + 6 cm = 17.5 cm
(ii) Perimeter of ∆ABC = 8 cm + 6 cm + 6 cm = 20 cm
(iii) Perimeter of ∆PQR = 4 cm + 3 cm + 5 cm = 12 cm
7. Find the perimeter of the given shapes.
Solution:
(i) Perimeter = PQ + QR + RS + ST + TU + UV + VP
= 2.5 cm + 3 cm + 2 cm + 3 cm + 2.5 cm + 4 cm + 4 cm
= 21 cm
(ii) Perimeter = PQ + QR + RS + SP
= 4 cm + 4 cm + 4 cm + 4 cm
= 16 cm
(iii) Perimeter = PQ + QR + RS + ST + TP
= 7 cm + 6 cm + 4 cm + 3 cm + 5 cm
= 25 cm
8. How to find the perimeter of a triangle?
Find the perimeter of the given triangle.
Solution:
To find the perimeter of a triangle, we measure the three sides of the triangle and add them together.
In the above given figure,
AB = 4 cm
BC = 8 cm and
AC = 7 cm.
Therefore, perimeter of the triangle = 4 cm + 8 cm + 7 cm
= 19 cm
Word Problems on Perimeter of a Triangle:
1. Two sides of a triangle are 3 cm and 4 cm. Find the third side of the triangle if its perimeter is 11 cm.
Solution:
First side of the triangle = 3 cm
Second side of the triangle = 4 cm
Perimeter of the triangle = Sum of the lengths of sides
i.e. sum of the lengths of the sides = 11 cm
3 cm + 4 cm + length of the third side = 11 cm
7 cm + length of the third side = 11 cm
But we know that 7 cm + 4 cm = 11 cm (Note: 11 – 7 = 4)
Therefore, length of the third side = 4 cm
Worksheet on Perimeter of a Triangle:
1. A triangle has a perimeter of 50 cm. If its two sides are of lengths 15 cm and 19 cm, what is the length of the third side?
Answer: 16 cm
2. Find the perimeter of each of the following triangles:
Answer:
2. (i) Perimeter of the triangle 12 cm.
(ii) Perimeter of the triangle 15 cm.
(iii) Perimeter of the triangle 18 cm.
(iv) Perimeter of the triangle 15 cm.
3. Finding missing side length of the triangle when perimeter is given:
Answer:
3. 5 cm
You might like these
Constructing a Line Segment |Construction of Line Segment|Constructing
We will discuss here about constructing a line segment. We know how to draw a line segment of a certain length. Suppose we want to draw a line segment of 4.5 cm length.
Worksheet on Line Symmetry | Geometry Worksheet | Line of Symmetry
Worksheet on line symmetry we will solve different types of questions. 4th grade students can practice this geometry worksheet to get the basic ideas on line symmetry. Fill in the blanks: (i) A square has …... lines of symmetry. (ii) An equilateral triangle has
Symmetrical Shapes | One, Two, Three, Four & Many-line Symmetry
Symmetrical shapes are discussed here in this topic. Any object or shape which can be cut in two equal halves in such a way that both the parts are exactly the same is called symmetrical. The line which divides the shape is called the symmetry. So, if we place a mirror
Different Types of Polygons | Triangle, Quadrilateral|Pentagon|Hexagon
The different types of polygons are discussed here. In any polygon a pair of sides that are inclined to each other meet at a point. This point is called a vertex of the polygon. In the polygon there
What is a Quadrilateral? | Symbol of a Quadrilateral □ | Rectangle
What is a quadrilateral? A simple closed curve or a polygon formed by four line-segments is called a quadrilateral.
Classification of Angles | Types of Angles | Acute, Right, Obtuse, ...
Classification of angles on the basis of their degree measures are given below: Acute angle: An angle whose measure is more than 0° but less than 90° is called an acute angle. Angles having mag
Measuring an Angle | Using Protractor | Comparison of Angles | Example
We will discuss here about measuring an angle with the help of a protractor. You can find it in your Geometry Box. It has the semi-circular shape. Its semi-circular edge is divided
Comparing Different Line Segments | Difference of two line segments
We will discuss here about comparing different line segments. Different line segments can be of different lengths. We can compare the lengths of the different line segments
Circle Math | Parts of a Circle | Terms Related to the Circle | Symbol
In circle math the terms related to the circle are discussed here. A circle is such a closed curve whose every point is equidistant from a fixed point called its centre. The symbol of circle is O. We have learned to draw a circle, by tracing the outlines of objects like a
What is a Triangle? | Types of Triangle | Scalene Triangle | Isosceles
A simple closed curve or a polygon formed by three line-segments (sides) is called a triangle. The above shown shapes are triangles. The symbol of a triangle is ∆. A triangle is a polygon with three sides. In the given figure ABC is a triangle. AB, BC and CA are its sides.
What is a Polygon? | Simple Closed Curve | Triangle | Quadrilateral
What is a polygon? A simple closed curve made of three or more line-segments is called a polygon. A polygon has at least three line-segments.
Simple Closed Curves | Types of Closed Curves | Collection of Curves
In simple closed curves the shapes are closed by line-segments or by a curved line. Triangle, quadrilateral, circle, etc., are examples of closed curves.
Measuring the Line Segment | Comparing Line Segments
We will discuss here about measuring the line segment i.e. how to draw and measure a line segment using scale or ruler. We can measure a line segment by two ways. (i) With the help of scale
Perimeter of a Square | How to Find the Perimeter of Square? |Examples
We will discuss here how to find the perimeter of a square. Perimeter of a square is the total length (distance) of the boundary of a square. We know that all the sides of a square are equal. Perimeter of a Square Perimeter of the square ABCD = AB+BC+CD+AD=2 cm+2cm+2cm+2cm
Perimeter of a Rectangle | How to Find the Perimeter of a Rectangle?
We will discuss here how to find the perimeter of a rectangle. We know perimeter of a rectangle is the total length (distance) of the boundary of a rectangle. ABCD is a rectangle. We know that the opposite sides of a rectangle are equal. AB = CD = 5 cm and BC = AD = 3 cm
● Related Concepts
● To Measure the Length of a Line-segment
● Examples on Unit of Mass or Weight
● Units for The Measurement of Capacity
● Examples on Measurement of Capacity
● Antemeridian (a.m.) or Postmeridian (p.m.)
● Calendar
● Reading and Interpreting a Calendar
4th Grade Math Activities
From Perimeter of a Triangle to HOME PAGE
Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.
Recent Articles
-
3-digit Numbers on an Abacus | Learning Three Digit Numbers | Math
Oct 08, 24 10:53 AM
We already know about hundreds, tens and ones. Now let us learn how to represent 3-digit numbers on an abacus. We know, an abacus is a tool or a toy for counting. An abacus which has three rods. -
Names of Three Digit Numbers | Place Value |2- Digit Numbers|Worksheet
Oct 07, 24 04:07 PM
How to write the names of three digit numbers? (i) The name of one-digit numbers are according to the names of the digits 1 (one), 2 (two), 3 (three), 4 (four), 5 (five), 6 (six), 7 (seven) -
Worksheets on Number Names | Printable Math Worksheets for Kids
Oct 07, 24 03:29 PM
Traceable math worksheets on number names for kids in words from one to ten will be very helpful so that kids can practice the easy way to read each numbers in words. -
The Number 100 | One Hundred | The Smallest 3 Digit Number | Math
Oct 07, 24 03:13 PM
The greatest 1-digit number is 9 The greatest 2-digit number is 99 The smallest 1-digit number is 0 The smallest 2-digit number is 10 If we add 1 to the greatest number, we get the smallest number of… -
Missing Numbers Worksheet | Missing Numerals |Free Worksheets for Kids
Oct 07, 24 12:01 PM
Math practice on missing numbers worksheet will help the kids to know the numbers serially. Kids find difficult to memorize the numbers from 1 to 100 in the age of primary, we can understand the menta
New! Comments
Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.