private void cboShapeTypeItemStateChanged(java.awt.event.ItemEvent evt) {//GEN-FIRST:event_cboShapeTypeItemStateChanged
        // TODO add your handling code here:
        //adding helpful volume displays
        int shapeIndexDisplayValue = cboShapeType.getSelectedIndex();
        
        if (shapeIndexDisplayValue == 0) {
            lblFormulaDisplay.setText("Length * Width * Height");
        } else if (shapeIndexDisplayValue == 1) {
            lblFormulaDisplay.setText("Pi * radius * radius * height"); 
        } else if (shapeIndexDisplayValue == 2) {
            lblFormulaDisplay.setText("(Pi * radius * radius * height) divided by 3");
        } else if (shapeIndexDisplayValue == 3){
            lblFormulaDisplay.setText("4/3 * Pi * radius * radius * radius"); 
        }
    }//GEN-LAST:event_cboShapeTypeItemStateChanged