Final answer:
The number 2.13 x 10^8 contains three significant figures, with '2.13' having the significant digits and '10^8' positioning the decimal point.
Step-by-step explanation:
The number 2.13 x 10^8 has three significant figures. The significant figures in a number are all the non-zero digits, any zeros between non-zero digits, and any trailing zeros in the decimal portion. In this case, '2.13' contains all of the significant figures for this number. The '10^8' is part of the scientific notation that indicates the decimal point's placement, but it does not affect the count of significant figures.