Your answer would be the third option, 55 inches.
Because this triangle is a right triangle, we can use Pythagoras's Theorem, c² - b² = a², where 'c' is the hypotenuse and 'b' is a leg, to find the third side.
This gives us:
73² - 48² = 5,329 - 2,304 = 3,025
√3025 = 55.
So 55 is your answer.
I hope this helps!
