<div id="container"></div>
html, body, #container {
width: 100%;
height: 100%;
margin: 0;
padding: 0;
}
var stage = acgraph.create("container");
var triangle = stage.triangleUp(100, 100, 100);
triangle.fill("#90CAF9");
var rectangle = stage.rect();
// Gets bounds.
var bounds = triangle.getBounds();
rectangle.setBounds(bounds);