Your answer would be the last option, 80 cm.
As this is a right triangle, you can use Pythagoras's Theorem, a² + b² = c², where 'c' is the hypotenuse and 'a' and 'b' are the legs, to find the missing side.
This gives us:
48² + 64² = 2,304 + 4,096 = 6,400
√6,400 = 80
So 80 is your answer.
I hope this helps!
