80% of 20 is 80/100 x 20 = 16
So, kelly has used 16 stamps, and has 4 left
The length of the unknown side length, |AB|, is 6.97
<h3>Trigonometry</h3>
From the question, we are to determine the value of the unknown side length
The unknown side length is the hypotenuse
Using SOH CAH TOA
We can write that
sin 35° = 4/|AB|
∴ |AB| = 4 /sin35°
|AB| = 4 /sin35°
|AB| = 6.97
Hence, the length of the unknown side length, |AB|, is 6.97
Learn more on Trigonometry here: brainly.com/question/22099203
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The correct answer would be D, because there’s no other leading common factors between the two besides one.