Geometry: Perimeter of Polygons
More Lessons on Geometry
In these lessons, we will learn the perimeter of the following polygons:
- square
- rectangle
- parallelogram
- triangle
- rhombus
- trapezoid
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, circumference 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.
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.
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.
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
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.
Perimeter of a rhombus = s + s + s + s = 4s
where s is the length of one side
Perimeter of a 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
How to find the Perimeter of a Rectangle? How to find the Perimeter of a Parallelogram? How to find the Perimeter of a Trapezoid? How to find the perimeters of rectangles, squares, triangles and other polygons?Word Problems involving perimeter of polygons
Example: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? Example:
The length of a rectangle is 7 cm more than 4 times its width. It perimeter is 124 cm. Find its dimensions. Example:
The width of a rectangle is 4 ft smaller than 3 times its length. Its perimeter is 144 ft. Find its dimensions.
Example:
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? Example:
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?
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