Hello all, I am a newbie in C#, need some advice from you masters. Follow is the excercise from my textbook "C Sharp for Students" Using the following value: double radius = 7.5; use assignment statements to calculate the circumference of a circle, the area of a circle and the volume of a sphere, based on the same radius. Display the results with message boxes. The messages should state what the result is rather than merely displaying a number. These calculations involve the use of Pi, which is 3.14 approximately. However, C# provides us with this value to more digits of precision. It is part of the Math class, and the following formulae show its use: circumference = 2 * Math.PI * radius; area = Math.PI * radius * radius; volume = (4 * Math.PI / 3) * radius * radius * radius; My codes to the exercise: Code: private void button2_Click(object sender, EventArgs e) { double radius = 7.5; double circumference = 2 * Math.PI * radius; double area = Math.PI * radius * radius; double volume = (4 * Math.PI / 3) * radius * radius * radius; MessageBox.Show("Circumference is " + Convert.ToString(circumference)); MessageBox.Show("Area is " + Convert.ToString(area)); MessageBox.Show("Volume is " + Convert.ToString(volume)); } Did it look OK to you? What I am not happy about is my declaration of variables, is it correct (in a way) to have them all as double? But then the results rather messy i.e. more than 2 digits after the decimal point. I left radius as double and changed the rest to integer but received the following error Code: Error 1 Cannot implicitly convert type 'double' to 'int'. An explicit conversion exists (are you missing a cast?) Is there a way to have the result with only 2 decimal places rather than e.g. circumference is 47.1238898038469 Thanks a lot for your advice