How To Work Out The Side Length Of A Square Given The Diagonal Length By Using Pythagoras

In this latest video you will be shown how to work out the side length of a square given its diagonal length. To do this you will need to substitute the sides into the Pythagorean formula a^2+b^2=c^2.

So in example 1 you need to work out the side length of a square given the diagonal length of 6cm. Since the square is divided into 2 right angled triangles you can use shorter side Pythagoras to find the side length of the square. Call the 2 sides of the square x (a and b) and 6 will be the longest side (c). So x^2+x^2=6^2, which gives 2x^2=36. So to find x divide 36 by 2 to give 18 and the square root of 18 is 4.2cm rounded to the decimal place.