[b]Proportional Co-Variation extends from the naturals to the reals.[/b][br][br][color=#0a971e][b]Line segments are proportional to the real numbers they can represent.[/b][/color][br]For a fun applet showing [b]multiplication [/b]via [b]circles[/b], goto [url]http://bit.ly/Multiplication_with_a_Circle[/url] [br]For a fun applet showing [b]division [/b]via [b]circles[/b], goto [url]http://bit.ly/Division_with_a_Circle[/url] [br]For a fun applet showing [b]square roots [/b]via [b]semi-circles[/b], goto [url]http://bit.ly/Square_Roots_via_a_Semi-Circle[/url][br][br][b]DRAG [color=#1551b5]FACTOR A •[/color][/b] ← or → and [color=#0a971e][b]FACTOR B •[/b][/color] ↑ or ↓ with your mouse.[br][color=#c51414][b]MOVE IMAGE[/b][/color] > Hold Shift and move the diagram on the screen with your mouse. [br][color=#c51414][b]ZOOM IMAGE[/b][/color] > Hold Shift and zoom in and out with your mouse wheel.[br][color=#c51414][b]ENTER FACTORS[/b][/color] > As well as dragging the factors with your mouse you can also enter factors into the [color=#1551b5]A[/color] and [color=#0a971e]B[/color] input boxes. [br][b]Reset the Applet[/b] to the default -ℯ × -π by clicking the icon top right [b][i](See further comments below the applet.)[/i]