Answer:
3
Step-by-step explanation:
Given
f(x) =
, then
f(12) =
=
= ± 3
There are 2 values 3 and - 3
The positive value of f(12) is + 3
The longest side of the triangle has to be less than the sum of the two other sides.
A ⇒ 7 + 8 = 15
B ⇒ 8 + 5 < 14
C ⇒ 6 + 3 < 10
D ⇒ 2 + 6 > 7
The answer is D, because the longest side length (7) is shorter than the two other side lengths (2 and 6).
I think the answer is 263.52. Hope it's right!
The answer for 2 is 192. The answer for 4 is 672.