Hey there! I'm happy to help!
In a 30-60-90 triangle, the shorter leg is always 1/2 of the hypotenuse. This can be proven using many different methods and there a lot of interesting videos out there about it. This is useful in geometry, trigonometry, and more.
So, if we know that the shortest leg is 12, we can make the following equation. We will have h represent the hypotenuse.
1/2h=12
Now, we simply divide both sides by 1/2 (which is the same as multiplying both sides by two.
h=24
Therefore, the hypotenuse is C) 24.
I hope that this helps! Have a wonderful day!