The side of a square is 11.2 cm. what is the length of the diagonal

You can work out the diagonal by using Pythagoras theorem. (a^2 = b^2 + c^2)

As it is a square, all 4 sides are the same so it would be:

11.2^2 + 11.2^2 = diagonal^2

250.88 = diagonal^2

Square root both sides to get what the diagonal is equal to.

diagonal is 15.8 cm