3.5.1 Perimeter
A perimeter is the total length of the boundary or outer edge of a two-dimensional shape. It is the sum of all the sides or edges of the shape.
The perimeter is usually measured in units such as centimeters, meters, inches, or feet, depending on the system of measurement used.
For example
The perimeter of a square is four times the length of one of its sides
To find the perimeter of a two-dimensional shape, you need to add up the lengths of all its sides.
The formula for finding the perimeter of different two-dimensional shapes are as follows.
Perimeter of a rectangle:
The perimeter of a rectangle is given by the formula
\( P = 2(l + b) \)
where “\( l \)” is the length and “\( b \)” is the breadth of the rectangle.
To find the perimeter, add the length and breadth of the rectangle and multiply the sum by \( 2 \).
Perimeter of a square:
The perimeter of a square is given by the formula
\( P = 4s \)
where “\( s \)” is the length of one side of the square.
To find the perimeter of a square, multiply the length of one side by \( 4 \).
Perimeter of a triangle:
The perimeter of a triangle is given by the formula
\( P = a + b + c \)
where “\( a \)”, “\( b \)”, and “\( c \)” are the lengths of the sides of the triangle.
To find the perimeter of a triangle, add the lengths of all its sides.
Perimeter of a circle:
The perimeter of a circle is called the circumference and is given by the formula
\( C = 2πr \)
where “\( r \)” is the radius of the circle and “” is a mathematical constant approximately equal to \( 3.14159 \).
To find the perimeter of a circle, multiply the radius by \( 2 \) and then multiply the result by “\( π \)”.
Once you have found the length of all the sides of the two-dimensional shape, you can add them together to find the perimeter.