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Diagonal Calculator

Choose the known values, enter them, and calculate the diagonal of rectangles, squares, or other shapes instantly and accurately.

millimeters (mm)

centimeters (cm)

meters (m)

kilometers (km)

inches (in)

feets (ft)

yards (yd)

miles (mi)

millimeters (mm)

centimeters (cm)

meters (m)

kilometers (km)

inches (in)

feets (ft)

yards (yd)

miles (mi)

square millimeters (mm²)

square centimeters (cm²)

square meters (m²)

square kilometers (km²)

square inches (in²)

square feets (ft²)

square yards (yd²)

square miles (mi²)

(a)

(da)

(ha)

(ac)

millimeters (mm)

centimeters (cm)

meters (m)

kilometers (km)

inches (in)

feets (ft)

yards (yd)

miles (mi)

degrees (deg)

radians (rad)

gradians (gon)

* π rad (pirad)

millimeters (mm)

centimeters (cm)

meters (m)

kilometers (km)

inches (in)

feets (ft)

yards (yd)

miles (mi)

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Diagonal Calculator

The diagonal calculator helps you find the diagonal, area, perimeter, and diagonal angles of a rectangle. Simply enter any two known values (length & width, area & one side, or perimeter & one side) to calculate the diagonal and other properties.

Diagonal of a Rectangle

A Rectangle is a quadrilateral having four angles and all the angles are 90 degrees. The opposite sides of the rectangle are parallel and equal in length. The adjacent sides of the rectangle are different in length, but the diagonals are equal in length and intersect in the middle point of the rectangle. We need to enter the length and width in the rectangle diagonal calculator to find the diagonal of the rectangle.

diagonal of a rectangle

Formula for Diagonal

You can calculate the diagonal using the Pythagorean theorem:

Diagonal: D = √(l² + w²)

  • l = Length of the rectangle
  • w = Width of the rectangle

Other Rectangle Measurements

Area: A = l × w

Perimeter: P = 2(l + w) = 2l + 2w

How to Find the Diagonal of a Rectangle?

We can find diagonal of a rectangle as: Diagonal = √(l² + w²)  Where: I = Length of the Rectangle W = Width of Rectangle

Area of a Rectangle:

We can find the Area of the Rectangle by multiplying the length and width: Area = l× w

The Perimeter of a Rectangle:

The perimeter of the rectangle can be measured by the given formula:

Perimeter = 2l + 2w=2(l+w)

properties of diagonal of a rectangle

Possibilities of Diagonal of Rectangle Measurements:

We can encounter various possibilities to find diagonal of a rectangle.

From Area and Length:

First, we have to find the length by the given formula:

l= A /w 

Then,

P = 2l + 2w

Diagonal length of a rectangle = √(l² + w²) 

From Area and Width:

First, we have to find the width:

w= A / l

P = 2l + 2w

The diagonal measurement of a rectangle can be done as:

Diagonal = √(l² + w²) 

From Perimeter and Length:

w = (P - 2l) / 2

Area = l× w

Diagonal = √(l² + w²) 

From Perimeter and Width:

l= (P - 2w) / 2

Area = l× w

Diagonal = √(l² + w²) 

Practical Example

Measure the length of the diagonal, area, and perimeter of a rectangle whose length is 4 units and width is 3 units.

Sol:

  • Length = 4 units
  • Width = 3 units

Substituting the values in the below equation  

Diagonal = √(l² + w²)= √(4² + 3²)  = √(25²)

The rectangle diameter = 5 units.  

Length of diagonal of a rectangle= 5 units.    

Area of rectangle = l× w

Area of rectangle = 4× 3 = 12 unit²

Perimeter of the rectangle  = 2l + 2w 

Perimeter of the rectangle  = 2(4) + 2(3)

The perimeter of the rectangle  = 8+ 6

The perimeter of the rectangle  = 14 units

How to Use the Diagonal Calculator?

Stick to the following steps for precise calculations by the diagonal measurement calculator

Input:

  • Enter any two known values (length & width, area & one side, or perimeter & one side)
  • click calculate

Output:

Our Diagonal of a Rectangle Calculator provides you with the following values:

  • Diagonal of the rectangle
  • Area of the rectangle
  • Perimeter of the rectangle
  • Circumcircle of the rectangle
  • Diagonal angle of the rectangle

References:

From Wikipedia: Circumscribed Circles

From WikiHow: Diagonal, Length, and Width

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