To find the probability of the complement of Event [tex]\( A \)[/tex], we use the fundamental rule of complements in probability. The rule states that the probability of the complement of an event [tex]\( A \)[/tex], denoted as [tex]\( P(A^c) \)[/tex], is equal to one minus the probability of the event [tex]\( A \)[/tex]. Mathematically, this is expressed as:
[tex]\[ P(A^c) = 1 - P(A) \][/tex]
Given that [tex]\( P(A) = 0.45 \)[/tex], we substitute this value into the formula:
[tex]\[ P(A^c) = 1 - 0.45 \][/tex]
When we perform the subtraction, we get:
[tex]\[ P(A^c) = 0.55 \][/tex]
So, the probability of the complement of Event [tex]\( A \)[/tex] is [tex]\( 0.55 \)[/tex].
Therefore, the correct answer is:
0.55
