5th Class Mathematics Area, Perimeter and Volume Area, Perimetre and Volume of Geometrical Figures

Area, Perimetre and Volume of Geometrical Figures

Category : 5th Class

 

Area, Perimetre and Volume of Geometrical Figures

 

Perimeter

Perimeter is referred as the length of the boundary line, which surrounds the area occupied by a geometrical shape.

 

  • Example:

Find the perimeter of the following figure.

 

                                                                      

Solution: Perimeter of the figure =

\[4\text{ }cm+3\text{ }cm+4\text{ }cm+2.5\text{ }cm+5\text{ }cm+5\text{ }cm\]\[=23.50\text{ }cm.\]

 

Perimeter of the Triangles

A triangles has three sides. Perimeter of a triangle is the sum of its all the three sides.

 

Perimeter of the triangle \[ABC=AB+BC+CA\]

 

  • Example

Find the perimeter of the following triangle.

 

Solution: Perimeter of the triangle PQR

\[\begin{array}{*{35}{l}}

   =4\text{ }cm+4.7\text{ }cm+6\text{ }cm  \\

   =14.7\text{ }cm  \\

\end{array}\]

 

Perimeter of the Quadrilateral

Perimeter of a quadrilateral is the sum of the length of its four sides.

 

In quadrilateral ABCD, perimeter

\[=AB+BC+CD+DA\]

 

  • Example

Find the perimeter of the following quadrilateral.

 

Solution: Perimeter of the quadrilateral

\[=5\text{ }cm+3\text{ }cm+4\text{ }cm+3\text{ }cm=15\text{ }cm\]

 

Perimeter of Rectangles

Perimeter of a rectangle\[=2\text{ (}Length+Breadth)\].

                                                                     

  • Example

Find the perimeter of the rectangle whose length is 12 cm and breadth is 8 cm.

Solution: Perimeter of the rectangle

\[=2\text{ (12}+8)=40\,\,cm.\]

 

Perimeter of Squares

Perimeter of a square\[=4\times side\].            

                                                                              

Perimeter of the square ABCD = \[=4\times AB\]

 

  • Example:

Find the perimeter of the square whose length of one side is 9 cm.

Solution: Perimeter of a square

\[=4\times 9\text{ }cm=36\text{ }cm\]

 

Area 

All the geometrical shapes occupies some space. The occupied space by a geometrical shape is called area of that geometrical shape.

                                                                                         

 

Shaded part in the above figures represent area.

Unit of the area is \[c{{m}^{2}}\] or \[{{m}^{2}}\].

 

Area of a Triangle

Area of a triangle = \[\frac{1}{2}\times base\times height.\]

Where base is the one side of a triangle and height is length of line segment drawn \[90{}^\circ \]on the base of that triangle.

 

  • Example:

Find the area of the triangle whose base is 75 cm and height is 80 cm.

Solution: Area of the triangle

\[=\frac{1}{2}\times 75cm\times 80cm=3000c{{m}^{2}}\]

 

Area of a Rectangle

Area of a rectangle = length \[\times \] breadth.

Area of the rectangle PQRS \[=PQ\times QR.\]

 

  • Example:

Find the area of the rectangle whose length is 17 cm and breadth is 15 cm.

Solution: Area of the rectangle

\[=17\text{ }cm\times 15\text{ }cm=255\text{ }c{{m}^{2}}\]

 

Area of a Square

Area of a square \[=sid{{e}^{2}}=side\times side\]

                                                                           

 

Area of the square PQRS\[=PQ\times PQ=P{{Q}^{2}}\]

 

  • Example:

Find the area of the square whose length of each side is 21 cm.        

Solution: Area of the square

\[=21\text{ }cm\times 21\text{ }cm=441\text{ }c{{m}^{2}}\]

 

Volume

In our daily life the number of things is stored in different kinds of container. Holding capacity of a container is called volume.

           

                                                            

 

Volume of a Cuboid

Volume of a cuboid =\[length\times breadth\times height=lbh\].

Where, length = AB, breadth = AE and height = BC

Volume of the cuboid ABCDEFG\[=AB\times BC\times AE.\]

 

  • Example:

Find the volume of the cuboid whose length, breadth and height are 15 cm, 13 cm and 14 cm respectively.

Solution: Volume of the cuboid

\[=15\text{ }cm\times 13\text{ }cm\times 14\text{ }cm=2730\text{ }c{{m}^{3}}\]

 

Volume of a Cube

Volume of a cube \[=sid{{e}^{3}}=side\times side\times side\]

  • Example:

Find the volume of the cube whose length is 19 cm.

Solution: Volume of the cube

\[=19cm\times 19cm\times 19cm=6859c{{m}^{3}}\]

 

 

Notes - Area, Perimetre and Volume of Geometrical Figures


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