First of all, with 30-60-90 triangles, we know this ratio applies:
Shortest side: middle length side: hypotenuse
1 : √3 : 2
Therefore, with this is mind, the only correct answer out of a,b,c and d is b.
Finally, to further prove b is correct, let us check with the ratio:
Ratio: 1 : √3 : 2
Option b 6 : 6√3 : 12
So as you can see, Option b matches with the 30-60-90 ratio.
(Each ratio number can be divided by 6 to get the 30-60-90 ratio.)
Hope this helps!
