Answer
c = 1.93
Explanation
Graphically, the probability: P(-c ≤ Z ≤ c) is represented by the area under the curve of z-scores, that is,
Given that the curve is symmetrical, then the area on the right is half the total area.
The probability: P(Z ≤ c) = 0.4732 is found in the following table:
The area of 0.4732 corresponds to P(z < 1.93), then c = 1.93