Answer: 5.6 cm
Step by Step: I used the same formula as the question before and I got the answer for this question. When solving questions like this, you can work backwards from the problem and then solve
3.61 is the answer because there is only two numbers after the decimal
Let the original number be x
X^2 + 11 = 36
Subtract 11
X^2 = 25
Square root both
X = 5
Solution: her original number is 5
I assume you mean to ask how to find the sum of the seven terms?
You have



...

So the sum is

You know that

and

, so the sum is equal to