For more, see Selection Tools
To activate: Toolbar
Selects features within a specified radius distance from a chosen point on the map view. Any feature on the current layer that crosses window, or is contained in the window, is selected.
To use:
Select the “Select by Radius” tool on the toolbar.
Click a point on the map view where features are to be selected.
Enter a search distance in the input box.
Press OK. The features that fall within the radius distance are highlighted in the map view.