Question

x 40. cm wrong value of number
✓ 4.0 x 10² cm correct number of sig figs and still has value of 400
in situations like this, the best option is to write the measurement in scientific notation.
400 cm with 2 significant digits is 4.0 x 10² cm.
which of the following gives the answer to the problem with the correct number of significant digits?
560 cm x 125 cm =?
a. 70000 cm²
b. 700 cm²
c. 7.000 x 10⁵ cm²
d. 7.00 x 10⁵ cm²
e. 7.0 x 10⁵ cm²

Explanation:

Step1: Multiply the values

$560\times125 = 70000$

Step2: Determine significant digits

560 has 2 significant digits, 125 has 3 significant digits. In multiplication, the result should have the least number of significant digits among the values being multiplied. So the result should have 2 significant digits.

Step3: Write in scientific notation

$70000$ written with 2 significant digits in scientific - notation is $7.0\times 10^{4}$

Answer:

e. $7.0\times 10^{5}\text{ cm}^2$