27.15 × 10^-4 in standard index form is
2.715 × 10^-3
To express 27.15 × 10^-4 in standard index form, we need to move the decimal point 4 places to the left because of the negative exponent. Doing so gives us:
27.15 × 10^-4 = 0.002715
27.15 × 10^-4 = 0.002715