Click Add to place a shape, then adjust its dimensions in Diagram.

Select labelled points in order from Points; available actions appear only for valid selections.

Use the lists to hide, show, or delete created segments, triangles, quadrilaterals, angles, and labels.

Use INSPECT on triangles and quadrilaterals to open an extracted 2D view for closer analysis.

If the view gets awkward, use Reset View. Use Share URL to copy a link to your diagram.

Desktop controls: left click + drag rotates, right click + drag pans, mouse wheel zooms, arrow keys rotate, and +/- zoom in/out.

On touch devices: drag to rotate, pinch to zoom, and use two-finger drag to pan.

For angle notation, ABC means the angle at B.