Method #1 – Side of Rectangle from the Perimeter
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Formula – How to calculate the width of a rectangle using the perimeter
Width = (Perimeter – (2 x Length)) ÷ 2
Example
A rectangle has a length of 10 and a perimeter of 80.
Width = (80 – (2 x 10)) ÷ 2 = (80 – 20) ÷ 2 = 60 ÷ 2 = 30
Method #2 – Width of Rectangle from the Area
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Formula – How to calculate the width of a rectangle from the area
Width = Area ÷ Length
Example
A rectangle has a length of 10 and an area 400.
Width = 400 ÷ 10 = 40
Method #3 – Width of Rectangle from the Diagonal
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Formula – How to calculate the width of a rectangle using the diagonal
Width = √(Diagonal2 – Length2)
Example
A rectangle has a length of 10 and a diagonal of 20.
Width = √(202 – 102) = √(400 – 100) = √300 = 17.32