How to Calculate the Diagonal of a Square

When working with squares and geometry, it’s occasionally necessary to calculate the length of the diagonal. A diagonal is a straight line joining two non-adjacent corners of a shape. In this article, you’ll learn a simple and effective method for calculating the diagonal of a square using the Pythagorean Theorem.
Understanding Squares and Diagonals:
A square is a quadrilateral – a polygon with four sides – that has equal-length sides and all four angles equal 90 degrees. The diagonals in a square are equal in length and bisect each other at a right angle (90 degrees).
Using the Pythagorean Theorem:
The Pythagorean theorem states that in any right-angled triangle, the square of the length of the hypotenuse (the side opposite to the right angle) is equal to the sum of the squares of the lengths of the other two sides. This can be expressed as:
c² = a² + b²
In case of a square, we can form two right-angled triangles by drawing one diagonal. Since all adjacent sides of a square are equal, we can denote one side’s length as ‘a’ (or ‘b’) and the diagonal’s length as ‘c’.
To calculate the diagonal:
Given that ‘a’ is one side’s length and ‘c’ is the diagonal length:
1. Multiply each side’s length by itself (a²).
2. Multiply that result by 2.
3. Take the square root of this final result.
Here’s how to do it with an example:
Suppose we have a square with sides measuring 4 units.
1. Calculate one side squared: 4 * 4 = 16.
2. Multiply that result by two: 16 * 2 = 32.
3. Take the square root of this final result: √32 ≈ 5.66
The diagonal measures approximately 5.66 units.
And there you have it! By using the Pythagorean theorem, you can easily calculate the length of the diagonal of a square. This method is not only helpful for squares but can also be used to measure the diagonal of any right-angled triangle or rectangle with ease.