Drag objects in your sketch for several purposes: to reposition the objects, to resize them, to change the shape of a construction, and to investigate the geometry embedded in the sketch, thereby discovering and revealing mathematical relationships between them.

Mathematically, moving an object in your sketch transforms that object, and Sketchpad’s dragging behavior is based on three geometric transformations: translation, rotation, and dilation. To allow you to use each of these transformations, Sketchpad has three Arrow tools: the Translate Arrow tool, the Rotate Arrow tool, and the Dilate Arrow tool.

To drag an object, position the tip of the Arrow tool over the object, and then press and drag. (The Arrow flips horizontal when it’s pointing at an object, and the status line describes the object that will be dragged.)

•If the object was not selected, only that object moves. (Any other selected objects are deselected.)

•If the object was already selected, it and all other selected objects move to follow your mouse.

When you drag an object, other related objects are adjusted to maintain their relationship to the dragged object. For instance, if you drag one endpoint of a segment, the segment adjusts to the new position of the endpoint you’re dragging. Similarly, if you drag the segment itself, both endpoints move with it. If you drag one vertex of a triangle, the two sides attached to that vertex adjust, and the third side remains unchanged. If you select and drag all three vertices, the entire triangle moves as a unit.

Multi-Touch Dragging: With a multi-touch capable SMART Board, it is possible to drag multiple objects independently, allowing several users to interact with the same sketch at the same time. For instance, three students might drag the three vertices of a triangle independently. (Contact the retailer or manufacturer of your SMART Board to determine whether your board is capable of multi-touch operation, and whether it has the required driver software installed. At the current time, this capability is limited to Windows computers.)

Drag a Straight Object to a Specific Angle