Perimeter of shapes

The perimeter of a figure is the distance around the outside of the figure. This is true whether the figure is a familiar figure like a rectangle or triangle, or if it is a complex figure like the floorplan of a house.

 

To find the perimeter of this figure, you need to add the lengths of all 6 sides.

Perimeter = 5 + 3 + 3 + 1 + 2 + 2 = 16 units

 

Since a rectangle has four sides with opposite sides being congruent, the formula for finding the perimeter is Side A + Side B + Side A + Side B. This could also be stated as $$\mbox{2•Side A + 2•Side B}$$ or $$\mbox{2•(Side A + Side B)}$$

 

To find the perimeter of a 4-by-6 rectangle you need to add the lengths of the four sides of the rectangle.

Perimeter = Side A + Side B + Side C + Side D

Perimeter = base + height + base + height

Perimeter = 6 + 4 + 6 + 4

Perimeter = 20 units

 


 

What is the perimeter of this rectangle?

Perimeter = Side A + Side B + Side C + Side D

Perimeter = base + height + base + height

Perimeter = 3 + 6 + 3 + 6

Perimeter = 18 units

 

  

 

Self-Check


Question 1

Find the perimeter of this figure.

 

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Question 2

Find the perimeter of this figure.

 

[show answer]


Question 3

Find the perimeter of this figure.

 

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