Final answer:
To calculate the product of 2.1 × 10² and 1.9 × 10⁷ in standard powers-of-10 notation, multiply the coefficients and add the exponents. The product is 3.99 × 10⁹.
Step-by-step explanation:
To calculate the product of 2.1 × 10² and 1.9 × 10⁷ in standard powers-of-10 notation, you need to multiply the coefficients (2.1 and 1.9) and add the exponents (2 and 7). Starting with the coefficients, 2.1 × 1.9 equals 3.99. Then, add the exponents, 2 + 7 equals 9. Therefore, the product is 3.99 × 10⁹ in standard powers-of-10 notation.