How many significant figures does the number 8,090 contain?

The number 8,090 contains four significant figures. When determining the number of significant figures in a number, it's important to consider which digits are significant. In this case, the digits 8, 0, 9, and the trailing 0 are all significant.

The first digit "8" is significant because it is a non-zero digit. The "0" that follows it is significant because it is between significant digits (8 and 9). The digit "9" is also significant as a non-zero digit. Lastly, the trailing "0" at the end of 8,090 is significant because it serves a purpose in indicating the precision of the measurement -- it shows that the number is indeed 8,090 and not 8,090 with additional digits that could imply a less precise measurement.

To summarize, all four digits in 8,090 are significant, leading to the conclusion that this number has four significant figures.