The expression that is not a variation of the Pythagorean identity is the third option.
<h3>
What is the Pythagorean identity?</h3>
The Pythagorean identity can be written as:

For example, if we subtract cos^2(x) on both sides we get the second option:

Which is a variation.
Now, let's divide both sides by cos^2(x).

Notice that the third expression in the options looks like this one, but the one on the right side is positive. The above expression is in did a variation of the Pythagorean identity, then the one written in the options (with the 1 instead of the -1) is incorrect, meaning that it is not a variation of the Pythagorean identity.
Concluding, the correct option is the third one.
If you want to learn more about the Pythagorean identity, you can read:
brainly.com/question/24287773
Answer: Meaghan is right.
Step-by-step explanation:
For a number like:
123.45
the tens place would be the "2" (second number at the left of the decimal point)
The ones place would be the "3" (first number at the left of the decimal point)
Let's suppose that Lily is correct.
Then the quotient of:
43.61/7
Will be a number with two digits in the left of the decimal point.
The smallest number that meets this condition, is the number 10.
Then let's see:
7*10 = 70
then:
70/7 = 10
and:
43.61 < 70
(70 is larger than 43.61)
then:
43.61/7 < 70/7 = 10
Then:
(43.61/7) < 10
This means that our quotient is smaller than 10, then the first digit of the quotient can not be on the tens place.
Then Meaghan is the correct one.
We also could perform the quotient to find:
43.61/7 = 6.23
So yes, Meaghan is correct.