Hex #99d377 or rgb(153,211,119) in RGB space is the tint of grass green. It has hue angle of 97.83 degrees, value = 83 and saturation = 44. #99d377 can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of blue, 3 drops of green, 4 drops of white.
Nearest safe hex - #99cc66. Below you can see the block with #99d377 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #99d377 to the mixer and play with it.