Workspace for Polygons
Plot a polygon.
Click '-' on points to hide the point values.
See the area as the value of poly1 (or q1 if a quadrilateral).
For perimeter, add segment values and/or use the command 'p=perimeter(poly1)' in the input bar. If a quadrilateral, use 'p=perimeter(q1)'.
Style it up with the style menu in the top right corner.