What is 0.0004605 rounded to 2 significant figures?

When rounding to 2 significant figures, we start counting from the first non-zero digit. In this case, the first non-zero digit is 4. The digit after 4 is 6, which is greater than 5, so we round the 4 up to 5. Therefore, 0.0004605 rounded to 2 significant figures is 0.00046.