To solve the equation \(a^2 = 6.4\), we first take the square root of both sides. This gives us two possible values for \(a\):
\[a = \sqrt{6.4} \quad \text{or} \quad a = -\sqrt{6.4}\]
Now, let's calculate \(\sqrt{6.4}\):
\[ \sqrt{6.4} \approx 2.529822 (to, 6, decimal, places) \]
Thus, the two potential solutions for \(a\) are approximately:
\[ a \approx 2.529822 \quad \text{or} \quad a \approx -2.529822 \]
Now, let's evaluate the options given:
- Choice A: \(a = -0.8\) (not a solution)
- Choice B: \(a = 0.8\) (not a solution)
- Choice C: \(a = -3.2\) (not a solution)
- Choice D: \(a = 3.2\) (not a solution)
- Choice E: None of the above (this is the correct answer)
Since none of the choices provided match our calculated solutions, the correct selection is:
\[ \text{(Choice E) None of the above} \]