The size of a television is measured as the length of the screenâ€™s diagonal, to the nearest centimetre. If the TV is 45cm long, 24cm high and 40cm deep, what size is it?
This may look like a volume question, but it is really just Pythagoras. The diagonal is the hypotenuse of the rectangle with sides 24cm and 45cm.
size: c^{2} = 45^{2} + 24^{2}
c^{2} = 2601
c = 51
so the size is 51cm