hi.... I want to change the font color and size for 1 line in richTextBox

enter code here

String [] Words = {"hi","hello","11111","he","she"}; richTextBox1.SelectionFont = new Font("Verdana", 10, FontStyle.Regular); richTextBox1.SelectionColor = Color.Blue; richTextBox1.SelectedText += Environment.NewLine + wo[0]; richTextBox1.SelectedText += Environment.NewLine + wo[1];
richTextBox1.SelectedText += Environment.NewLine + wo[2]; richTextBox1.SelectedText += Environment.NewLine + wo[3]; richTextBox1.SelectedText += Environment.NewLine + wo[4];

I want to change just the string "11111" and keep the rest lines as default any help