# Euclid's Muse

## your source for INTERACTIVE math apps

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You can drag the vertices of the shadow linkage to alter its geometry. Can you create a linkage which draws a figure 8?  How about the letter D?  How close to a straight line can you get? If you like this, you might like my 4 bar linkage clock app.

By Marissa
##### A Second Look at the Four Bar Linkage
From "Creating HTML5 Apps with Mechanical Expressions."

By Marissa
From "Creating HTML5 Apps with Mechanical Expressions."

##### Maximum Area Configuration of a Four Bar Linkage
You can set the lengths of the four bars in your linkage.  Then drag point B till you think it encloses the maximum area.  Click the button to examine the area. Click Solution to observe that the solution occurs where all four vertices lie on the same circle.

Watt’s approximate straight line linkage is used in automobile suspensions. Drag the red points to see the mechanism move. What is the angle of the approximate straight line? Press Show for a hint.

##### Area Under a 4 bar linkage
Drag B and find the configuration with the greatest area. Now press the Show Circle Button.  The circle is the circumcircle of A B and D.  Does C also lie on it? Now try to find the minimum area.

Tags: maximum, area-circumcircle, 4-bar

##### Four Bar linkage with line
The line has equation Ax+By+C=0 You can change line parameters and observe its location relative to the coupler curve. You can also press teh F button to see the coordinates of the coupler point F.