Question

A rectangle has a length of 9.00 inches and a width of 4.25 inches. What is the area in square inches? Round to the correct significant digits. DO I ADD UNITS?????

Answer 1

Both numbers (9.00 and 4.25) have three sig-figs. This means that the final answer will have three sig-figs as well.

Multiply the numbers to get: 9.00*4.25 = 38.25 which rounds to 38.3 because the answer must have three sig-figs. 

The units will be "square inches" or "inches^2" or "in^2". There are various ways to write the units portion.

Overall, the final answer is 38.3 square inches.