Final answer:
The probability that a randomly chosen letter in the word calculator has a vertical line of symmetry is 5/9 or approximately 0.5556.
Step-by-step explanation:
In the word calculator, there are 9 letters. To determine the probability that a randomly chosen letter has a vertical line of symmetry, we need to identify the letters that have a vertical line of symmetry. The letters that have a vertical line of symmetry are 'H', 'I', 'O', 'X', and 'Z'. Out of the 9 letters in the word calculator, 5 of them have a vertical line of symmetry.
Therefore, the probability that a randomly chosen letter in the word calculator has a vertical line of symmetry is 5/9 or approximately 0.5556.