A right angled triangle has two smaller sides length 3 and 4, what is the length of its longest side?

As we are told it is a right angled triangle we known that we can use Pythagoras's formula of c² = a²+b² given that we have been given lengths of 3 and 4 we simply substitute these into the equation c² = 3²+4² to give us c² = 25. We then square root our answer to find the length of c. c=5