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Answer:
A 12
Step-by-step explanation:
We can use the pythagorean theorem to find the length a
a^2 + b^2 = c^2
a^2 + (4sqrt(3))^2 = (8sqrt(3))^2
a^2 +16*3 = 64*3
a^2 +48 = 192
Subtract 48 from each side
a^2 +48-48 = 192-48
a^2 =144
Taking the square root of each side
sqrt(a^2) = sqrt(144)
a = 12
We only take the positive square root because length must be positive