To get the length of the hypotenuse, we use the equation a² + b² = c².
a and b are the lengths of the legs, and c is the hypotenuse. In this case, the legs are 3 and 4. So, plug them into the equation.
3² + 4² = c²
Now, solve for c
9 + 16 = c²
25 = c²
5 = c
Since c is 5, that means the hypotenuse is 5 cm.