using static System.Console;
 
public class Program {
	public static void Main() {
		var larguraText = "2.00";
		var alturaText = "1.00";
		var percText = "30";
		var total = 0.0;
		if (double.TryParse(larguraText, out var largura) && double.TryParse(alturaText, out var altura) && double.TryParse(percText, out var perc)) {
			total = largura * altura * (perc / 100);
		}
		var totalText = total.ToString(); //só para fins didáticos do exemplo
		WriteLine(totalText);
	}
}
 
//https://pt.stackoverflow.com/q/320182/101

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

MS43Ngo=

1.76