We know the sum of the internal angles in a triangle is always 180°. We also know that the sum of the internal angles in a quadrilateral is always 360°. What about the sum of the angles in a five-pointed star?

For this investigation, create *several* different five-pointed stars. Then measure the internal angles of the five points. Record your measurements in a table. **Use words, numbers, and pictures to clearly explain your findings.**

Examples of stars:

Use this applet to help with your investigation.

**Directions:**

- Create a 5-pointed star and then use the checkbox to "pin" the vertices down.
- Use the protractor to measure the five internal angles.

- Find the sum of the angles.
- Make a new star. Do you get similar results?

Angles in a Star Grading Rubric

Category |
1 |
2 |
3 |
4 |

Stars |
Stars are missing from the write-up. |
Stars have not been labeled with angle letters and/or degree measurements. |
Stars are shown with their angles clearly labeled with the letter and the degrees measurement, but there are not enough stars included. |
Several stars are shown with their angles clearly labeled with a letter and the degrees measurement. |

Use of protractor |
There are several protractor mistakes. |
Most angles have been measured correctly. |
Nearly every angle has been measured correctly. |
All angles have been accurately measured with a protractor. |

Table |
Table is messy or is missing important information. |
Table is messy and hard to read, but has all information. |
Table includes all necessary information, but is not particularly neat. |
Table is neatly drawn with a title for each column. Table includes all necessary information. |

Conclusion statement |
Conclusion is wrong and not in sentence form. |
The conclusion is incorrect, but at least it was written in sentence form. |
The conclusion is correct, but has not been written in sentence form. |
The conclusion is written in sentence form and the conclusion is correct. |

Neatness |
Paper is wrinkled. Writing is messy. Stars drawn poorly. |
Everything is easy to read, but the overall look is not neat and organized. |
All writing, mathematics, and stars are neat, easy to read. |
All writing, mathematics, and stars are neat, easy to read, and include color. |