I don't think you use a fraction. You multiply .6666 by 72 which equals 47.9952 or rounded 48. :)
Answer: c)
Step-by-step explanation:
This can be done through trial-and-error. Use the pythagoreas' theorem
and if the left side of the equation is equal to the right, that is the answer.
(Do take note that c is the longest side.)
a)


Since
, a) is wrong.
b)

Since
, b) is wrong.
c) (answer)

Since
, c) is correct.
d)

Since
, d) is wrong.