Using ExtJS 3.2.1 radiogroup after the radiobox is checked how do I ask for more data from user?

Question

Okay I am using different shapes and want volume.

My Radio groups are 1) Vertical Cylinder, 2) Square column, 3) Rectangular column, 4) Partial Conical, and 5) Horizontal Cylinder.

Okay I choose 1

Then in the Listener I want to to display the data fields to fill out to calulate the volume. ie radius and height nice to have: show a diagram (jpg file) of the shape and what I am asking for as well

                    listeners:{
                        change: function(field, newValue, oldValue, eOpts) {
                              if(newValue.inputValue == '1') {
                                items: [{
                                       xtype: 'field',
                                       fieldLabel: 'Height',
                                       allowBlank: false,
                                       name: 'VerticalCylinderHeight',
                                       id: 'VerticalCylinderHeight',
                                       width: 20,
                                     },{
                                       xtype: 'field',
                                       fieldLabel: 'Radius',
                                       allowBlank: false,
                                       name: 'VerticalCylinderRadius',
                                       id: 'VerticalCylinderRadius',
                                       width: 20,
                                    },

                                     ]

                            };
                        }}