Answer: 10.9
Explanation:
You would use Pythagorean theorem:
5x5+12x12=c
5x5=25
12x12=144
Now, 25+144=169
Now find the square root of 169 which is 13 which isn't an answer choice, which means your prolly after a leg.
I assume 12 is the hypotenuse
A(squared)+5x5=12x12
A+25=144
144-25=119
Square root of 119=10.9
So I'm going to go with answer 10 in or 11 if you round.