Where are you typing it? And did I understand your question correctly?
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Type in 1/4
I mean the fourth line of your first solution should look the same as the third line of your second solution.
It needs a further edit MG! 28 + 7x means 28 = minus 7x
In that case, in your first answer you got a sign wrong when you skipped it!
28+ 7x = 0 isn't the same as 28 = 7x, it's the same as 28 = -7x
When you add 9x to both sides MG you should get 28 + 7x = 0, not 28 = 7x
To change a decimal into a percentage, multiply by 100.
To change a percentage into a decimal, divide by 100.
Use 2nd followed by asin
The relationship between a side length (s) and a diagonal (d) for a regular pentagon is: sin(18°) = s/(2d)
Rearrange and plug in the numbers as required.
+33667 
