Final answer:
To find the number of which 17 is 0.21%, set up the equation 17 = 0.0021 * x, and solve for x to get 8095 when rounded to the proper number of significant figures.
Step-by-step explanation:
The student's question can be represented mathematically as 17 = 0.21% of x, where x is the unknown number we are trying to find. To solve for x, we can set up the equation 17 = 0.0021 * x (since 0.21% equals 0.0021 as a decimal). Dividing both sides of the equation by 0.0021 gives us x = 17 / 0.0021.
Calculating this, we get x = 8095.2381. Therefore, 17 is 0.21% of 8095.2381. When expressed with the proper number of significant figures, this answer rounds to x = 8095, since only two significant figures are present in the original percentage (0.21%).