Geometry: Perimeter of Polygons



In this lesson, we will learn the perimeter of the following polygons:

  • square
  • rectangle
  • parallelogram
  • triangle
  • rhombus
  • trapezoid

We will also learn how to solve word problems involving perimeter of polygons.

Related Topics:
More Lessons on Geometry

Perimeter of Polygons

The perimeter of a polygon is the sum of the lengths of its sides. It is the distance around the outside of the polygon.

See also area of circles, cicumference of circles.

Perimeter of a Square

Since the sides of a square are equal, the perimeter of a square is 4 times the length of its side.

square

Perimeter of a square = s + s + s + s = 4s

where s is the length of one side

Perimeter of a Rectangle

A rectangle has four sides, with opposite sides being equal in length.

rectangle

Perimeter of a rectangle = l + l + w + w = 2(l + w),

where l is the length and w is the width of the rectangle.

Worksheet 1, Worksheet 2, Worksheet 3 to calculate the area and perimeter of rectangles.

Perimeter of a Parallelogram

Similar to a rectangle, a parallelogram has four sides with opposite sides being equal in length.

parallelogram

Perimeter of a parallelogram = l + l + w + w = 2(l + w)

where l is the length and w is the width of the parallelogram.

Worksheet to calculate the area and perimeter of parallelograms

Perimeter of a Triangle

triangle

Perimeter of a triangle = a + b + c

where a, b and c are the lengths of each side of the triangle.

Perimeter of a Rhombus

A rhombus has 4 equal sides, so the perimeter of a rhombus is 4 times the length of its side.

rhombus

Perimeter of a rhombus = s + s + s + s = 4s

where s is the length of one side

Perimeter of a Trapezoid

trapezoid
a is parallel to b

Perimeter of a trapezoid = a + b + c + d

where a, b, c and d are the lengths of each side.

Videos

The following video shows how to find the Perimeter of a Rectangle

The following video shows how to find the Perimeter of a Parallelogram





The following video shows how to find the Perimeter of a Trapezoid



The following video shows how to find the perimeters of rectangles, squares, triangles and other polygons.





Word Problems involving perimeter of polygons

A rectangle is three times as long as it is wide. If the perimeter is 62 cm, what is the length?

The width of a rectangle is 6 cm less than the length. If the perimeter is 52 cm, what is the width?

 

The length of a rectangle is 7 cm more than 4 times its width. It perimeter is 124 cm. Find its dimensions.







The width of a rectangle is 4 ft smaller than 3 times its length. Its perimeter is 144 ft. Find its dimensions.



 

A rectangle garden is 2.5 times as long as it is wide. It has a perimeter of 1.6 feet. How long and wide is the garden?

 

The perimeter of a triangle is 26 cm. The first side is 6 cm shorter than the second side. The third side is 2 cm shorter than twice the length of the first side. What is the length of each side?







OML Search

We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.

Find Tutors

OML Search