Praxis II General Science (5435) Practice Test

To express the product of 91,000 and 87,000 in scientific notation while correctly applying significant figures, we first perform the multiplication. The two numbers can be approximated as 9.1 x 10^4 and 8.7 x 10^4 in scientific notation.

When multiplying these two numbers, we should multiply the coefficients (9.1 and 8.7) and then add the exponents from the powers of ten:

1. Multiply the coefficients: 9.1 * 8.7 = 79.17.

2. Add the exponents: 10^4 * 10^4 = 10^(4+4) = 10^8.

Thus, the product becomes 79.17 x 10^8.

Next, we need to round our coefficient (79.17) to two significant figures, since both original numbers have three significant figures. This rounding leads us to approximately 7.9.

Putting it all together, we express the result as 7.9 x 10^8. However, since we have 10^8, moving the decimal point in 7.9 one place to the right to be in scientific notation means we must adjust