# Perimeter meaning in math explained

Learn and know what is the perimeter meaning in geometry chapter. We will be listening the word “perimeter” frequently in the problems which are based on geometry.

Along with the perimeter, we should also know the meaning of “Area”. These are the two important words for which we have to know the meanings in geometry. Now we will learn the meaning of perimeter and we will learn perimeter formulas for some specified shapes.

## Exactly what is the perimeter meaning?

The meaning of perimeter is said to be “the outer boundary of the any shape is called as a perimeter”. For any polygon, perimeter is given by sum of all sides.

For the shapes which are made up of curves, for example circle. The outer boundary of circle is called as circumference not as perimeter.

### Some important perimeter formulas as follows:

As we know perimeter meaning, so easily we can list out perimeter formulas for some basic shapes.

• Perimeter of square with a side “a” is given as “4a” units.
• Perimeter of rectangle with length as “a” and breadth as “b” is given as 2 (a+b) units.
• Circumference of circle i.e. perimeter of circle is with radius “r” is given as 2πr units.
• Perimeter of a triangle with sides “a”, “b” and “c” is given as a+b+c units.
• Perimeter of equilateral triangle with a side “s” is given as “3s” units.
• Let the two equal sides of isosceles triangle be “a” and third side be “b” then perimeter of isosceles triangle is given by “2a+b” units.
• Perimeter of regular pentagon with a side “a” is given by “5a” units.
• Perimeter of regular hexagon with a side “a” is given by “6a” units.
• Perimeter of regular heptagon with a side “a” is given by “7a” units.
• Perimeter of regular octagon with a side “a” is given by “8a” units.
• Perimeter formula for the regular nonagon with a side “a” is given by “9a” units.
• Perimeter of regular decagon with a side “a” is given by “10a” units.