There are 2 basic trangles used in SAT,
45-45-90
30-60-90
if you look in the attachment you will know the relationship between each so
with a 30-60-90 triangle which you have
hypotonuse=2x
hypotonuse=12
2x=12
divide by 2
x=6
I'm not sure about the length, but I'm assuming you mean the longer side
the measure of each leg is 6 and 6 times√3
the lonnger one is 6√3
the answer is 6√3 meters
45-45-90
30-60-90
if you look in the attachment you will know the relationship between each so
with a 30-60-90 triangle which you have
hypotonuse=2x
hypotonuse=12
2x=12
divide by 2
x=6
I'm not sure about the length, but I'm assuming you mean the longer side
the measure of each leg is 6 and 6 times√3
the lonnger one is 6√3
the answer is 6√3 meters