I'm writing a code that generates a chart using google charts. And here is the original code.

```js
      google.charts.load('current', {'packages':['corechart']});
      google.charts.setOnLoadCallback(drawChart);

      function drawChart() {

        var data = google.visualization.arrayToDataTable([
          ['Task', 'Hours per Day'],
          ['Work',     11],
          ['Eat',      2],
          ['Commute',  2],
          ['Watch TV', 2],
          ['Sleep',    7]
        ]);

        var options = {
          title: 'My Daily Activities'
        };

        var chart = new google.visualization.PieChart(document.getElementById('piechart'));

        chart.draw(data, options);
      }
```

```html
<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
       <div id="piechart" style="width: 900px; height: 500px;"></div>

```

Here is my modification. Initially, I want the Pie chart not to be displayed. and when I click on the button it should comeup.

```js
google.charts.load('current', {
  'packages': ['corechart']
});
google.charts.setOnLoadCallback(drawChart);

function drawChart() {

  var data = google.visualization.arrayToDataTable([
    ['Task', 'Hours per Day'],
    ['Work', 11],
    ['Eat', 2],
    ['Commute', 2],
    ['Watch TV', 2],
    ['Sleep', 7]
  ]);

  var options = {
    title: 'My Daily Activities',
    pieSliceText: 'value',

  };

  var chart = new google.visualization.PieChart(document.getElementById('piechart'));

  chart.draw(data, options);
}

function showPie() {
  document.getElementById("piechart").style.display = '';
}
```

```html
<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
<div id="piechart" style="width: 900px; height: 500px; display:none"></div>
<button type="button" onclick="showPie()">Click Me!</button>
```

Even this is working fine, but my question is, why the size is coming down? Is there a way that I can retain the size even when I get the pieChart back. Please let me know on where am I going wrong and how can I fix it.

Thanks!!!