Final answer:
To find the sum of 39.48 and 26.7, you align the decimal points and add, resulting in a sum of 66.18 which is already expressed with three significant figures.
Step-by-step explanation:
To find the sum of 39.48 and 26.7, we can align the decimal points and add the numbers like we would with whole numbers, making sure to place the decimal point in the answer directly below the decimal points in the numbers being added. In this particular problem, 39.48 has two decimal places and 26.7 has only one, so we can think of it as 26.70 for consistency. Now, let's add:
39.48
+ 26.70
______
66.18
The sum is 66.18. We also need to consider significant figures. 39.48 has four significant figures and 26.7 has three. Therefore, our answer should be rounded to three significant figures, if necessary. In this case, it's not, as the sum 66.18 is already at three significant figures.