sin

To get the inverse sin key, click the  " 2nd "  key in the top left corner, then click the  " asin "  key, which is right below it. Then enter your number and close parenthesee.

 

Or, you can type this into the box:    asin(2.23/3.78)    and hit enter.

 

You should get....

 

asin(2.23/3.78)  ≈  36.153°          or          asin(2.23/3.78)  ≈  0.631 radians