You can change the angle between two segments, or change the length of a segment.
Make the shape editable. To learn how, see Making Shapes Editable.
Click a corner point.
To change the angle between the two attached segments, drag the point clockwise or counter-clockwise.
To change the length of one of the segments, drag the point outward or inward.
Add more editing points by holding down the Option key while you hold the pointer over a line. When the pointer takes the shape of a pen tip with a plus (+) sign, click where you want to add a new editing point.
For more information, see Adding, Deleting, and Moving the Editing Points on a Shape.
To learn about manipulating and aligning shapes, and changing their general object properties, such as color, border style (stroke), size, orientation, shadows, and more, see About Manipulating, Arranging, and Changing the Look of Objects.
To learn further details about modifying specific types of shapes, curves, and lines, see: