# Euclid's Muse

## your source for INTERACTIVE math apps

By Faith
##### Soda Cantastrophy

Tags: circle, radius, circumfrance, rate-of-change, related-rates, draggable

##### 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).

Tags: Twisted-Savonius, Wind-Turbine, Pseudo-3d, Model, Squeeze, Geometric, Real-World, Ellipses, Arcs, Loci, Parametric/Proportional

##### Geometric Top View Model of the Twisted Savonius Wind Turbine (Interactive)
This app models the top view of the Twisted Savonius Vertical Axis Wind Turbine (VAWT). The various inputs and draggable points allow you to see how the model can trace the blades' surfaces. You can also control the twist angle, radius, and rotation - which makes the whole thing spin! Learn more about the Twisted Savonius Modeling Project here.

Tags: Twisted-Savonius, Top-View, Model, Geometric, Real-World, Circles, Arcs, Loci

##### Tangential Circles
Can you come up with a formula for the radius of the third circle?

Tags: pappus, apollonian-circles

##### N-Gon Approximating a Circle
This n-gon (regular polygon of n sides) has a variable number of sides. Changing the value for n demonstrates very visually how regular polygons of increasing numbers of sides, with the same radius, have a shape that increasingly approaches that of a circle.

Tags: N-gons, circles