# Search Results for “proportional-position”

##### Circle Radius and Proportional Position Puzzler

Five circles are centered proportionally around an ellipse according to functions of the variable*r*. Each circle’s radius is defined by the same function as its position, of

*r*. Can you figure out the five functions of

*r*which define the five circles? Download the .gx source for the answer.

**Tip**: if you press the ”go” button, r will animate at a constant rate and the ellipse will stay a constant size. If your drag the slider, note that the ellipse is not changing size or position, but the app is zooming in and out in order to display everything within its window most efficiently.

*Hint: one circle’s radius and position are defined by*

**f**(r) = r.##### Squeezing Twisted Savonius Wind Turbine Model

This model demonstrates that the surface of the Twisted Savonius wind turbine's blades are geometrically squeezed as the twist angle is increased and the parametric position is moved up and down the turbine. Learn more about the squeeze. Learn more about the Geometry of the Twisted Savonius Wind Turbine project.*Note: the calculated radius in this particular example cannot be accurate because the model is a 2d geometric approximation of the real 3d shape. Accurate calculations are made from the top view model, which is visually more difficult to comprehend. The calculation here still varies accurately as the twist angle is changed and the position is moved up and down the turbine, but it also varies as the rotation is changed (which shouldn't happen).*