Answer:
The number given is 1.20 x 10^-17. To determine the number of significant figures in this number, we can use the following rules:All non-zero digits are significant. In this case, there are two non-zero digits, 1 and 2, so they are both significant.Zeros between non-zero digits are significant. In this case, there is one zero between the non-zero digits, so it is significant.Zeros to the left of the first non-zero digit are not significant. In this case, there are no zeros to the left of the first non-zero digit.Zeros to the right of the last non-zero digit are significant only if there is a decimal point present. In this case, there are no zeros to the right of the last non-zero digit, and there is no decimal point.Therefore, the number of significant figures in 1.20 x 10^-17 is 3.
Explanation: