7+8 is the answer
But it can also be 11
The answer choice is B I just took
The answer is 9. You multiply 1/4 three times which is 1/64 then take 576 and multiply it by 1/64 which gives you 9.
Its a obtuse angle since 7^2 is 49 7^2 is 49 and 12^2 is 144
144 is bigger than 90 so its obtuse triangle