The US postal service delivered 7.14 x 1010 pieces of mail in the month of December 7.14 x 1010=7211.4
3.21 x 1010 in the month of January. 3242.1
What is the total mail delivered for these two months?
7211.4
+ 3242.1
__________
10453 .5 TOTAL MAIL
The correct option about the proof is C. Both Amanda and Stephen are correct.
<h3>How to illustrate the information?</h3>
It should be noted that both Amanda and Stephan are correct as they are taking two different pairs of supplementary angles.
Amanda's proof is that he takes (∠1 and ∠4) and (∠3 and ∠4)as the supplementary angles and writes ∠1 + ∠4 = 180° and ∠3 + ∠4 = 180°,
Stephan's proof is that he takes (∠1 and ∠2) and (∠3 and ∠4) as the <em>supplementary</em> angle pair.
Therefore, the correct option is C.
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Answer:
There are total 30 books in the 5 feet high stack of books.
Step-by-step explanation:
The complete question is
Given, Each note book is 2 inches thick, How many notebooks do you think it would take to make a stack that is 5 feet high
Solution
Thickness of each book 
The total height of the book stack is
feet.
The number of books in the stack is equal to total height of the stack divided by the thickness of one book
Number of books in five feet high stack is

Hence, there are total 30 books in the 5 feet high stack of books.
Using proportions, it is found that:
- In an 8-hour day, she keys 48 pages.
- For a day, her gross earnings are of $72.
- For a week, her gross earnings are of 72 x 7 = $504.
<h3>Proportions:</h3>
This question is solved using the proportions given, which are:
- Payment of $1.50 per page of 30 lines.
- Retha keys 6 pages per hour.
Hence, in an 8-hour day, she keys 6 x 8 = 48 pages.
Since she earns $1.50 per page, for a day, her gross earnings are of 48 x 1.5 = $72.
Considering a week has 7 days, for a week, her gross earnings are of 72 x 7 = $504.
To learn more about proportions, you can take a look at brainly.com/question/24372153