For the first method, I got a value 39.23 for a value of 40% and for the second method, I got a value of 0.68 for the same percentage. Any explanation for the difference
Sainey - Keita, what do you mean by "correct"? The first result is in degrees, the second one in radians - both are correct within Excel's accuracy of calculations. They are equivalent from a formal point of view. The difference is in what units do you need for further calculations/data presentation.