# GeoGebra 3D: Getting Started

- Author:
- Tim Brzezinski

- Topic:
- Solids or 3D Shapes

Take a look at the GeoGebra applet below, but please don't touch it yet.
In this applet, the **black segment **is parallel the the **red line**.
Suppose we were to rotate (spin) this **black segment** 360 degrees (fully) about the **red line**.
What would be the resulting surface of revolution formed by doing so?
Write your guess/conjecture below.

In the applet above, slide the slider (named **n**) all the way to the right to test your conjecture.
What kind of surface do we get?

Take a look at the GeoGebra applet below.
In this applet, the **black segment **has one of its endpoints on the **red line**.
Suppose we were to rotate (spin) this **black segment** 360 degrees (fully) about the **red line**.
What would be the resulting surface of revolution formed by doing so?
Write your guess/conjecture below. Then, test your conjecture by sliding the black slider (named **n**) all the way to the right.

The GeoGebra applet below shows the surface of revolution formed by rotating the graph of the function **f(x) = sin(x) (from x = 0 to x = 4)** about the **xAxis**.
Notice how this surface looks like a fish.
How can we modify the function f above (upper left) to create a fish with an **OPEN MOUTH? ** Try it!
Any way to create a 3D surface that looks like **two fish that are kissing**? Try it!