Scaling an object or component changes its size. Scaling happens from the pivot of the object. If you have multiple objects selected, they scale from their common pivot point, which is the last object added to the selection (the key object). For components, the pivot point is located at the center of all selected components.
To scale objects or components
If you want to first change the settings for the Scale Tool, double-click its icon to display its options in the Tool Settings panel.
You can also scale objects or components with the Combined Move/Rotate/Scale manipulator.
To scale with precise values, see Move, rotate, and scale using precise values