Project 5

  • Project 5: Same polygons with different circles and a surprise (GER, RO, IT, CRO) 

    • Worksheet  and creative, common results (GER)

    • Looking for help from a student (GER) -> see here .
    • Student Sophia from Romania has sent it. Thank you! So we can now work on this project!

    You can change the settings here to get english subtitles!

    Continuations:

    • Finding the number of different carvings for pentagons, hexagons, ...
    • How many arrangements of triangles in a pentagon, hexagon, ... ?
    • Is there a formula for the number of different carvings?
    • Proof for pentagons, hexagons, ...
    • The circles could be animated at the end e.g. by rotation
       
    • Construction on paper (CRO)


     

    German students will talk about your work next week and give some comments in the Forum!

    • Proof of Japanese Theorem from Italian students first part: 

    A triangle is always cyclic. Let's prove the Japanese theorem, dividing it into parts. Let's start from "One and only one circle passes through three given non-collinear points" . and that these three points are even the vertices of a unique triangle. Let's explore some of the properties: the incenter and the incircle of the triangle and the inradius and the area.

    • Second Part:

    The circumcenter is the point where the perpendicular bisectors of a triangle intersect. The circumcenter is also the center of the triangle's circumcircle - the circle that passes through all three of the triangle's vertices. Let's explore the relation between the area of ABC the inradius and circumcenter.

    • Third Part

    Carnot's Theorem and Japanese Proof

    • Proof of  the Japanese Theorem through iteration by Norma Lisa Neiman 

    Carnot's Theorem

    Explaining through Carnot’s Theorem the Japanese Theorem.by Norma Lisa Neiman

  • Cooperation and communication in this project

    History 1

    Germany had the idea for a project (grade 5, 6) but we need a tool before starting

    History 2

    A Romanian student created a tool for the inner circle and uploaded it.

    History 3

    German students worked on pentagons (see worksheet) and made a surprising mathematical discovery. A common artwork was created, too.

    History 4

    German students asked older students in a video for a proof.

    History 5

    Croatian students constructed inner circles on paper and made the same discovery.

    History 6

    Italian students of grade 10 started with a proof of the theorem.

    History 7

    A talented German started and a trainee teacher and some teachers of the project starte with the proof, too.

    History 8

    We also looked on the internet for a proof. Up to now not found ;-)

    History 9

    Italian students of grade 9/10 started with a proof for triangles (two parts)in a video.

    History 10:

    A visual proof done by the Italian teacher.

    History 11

    Italian students of grade 9/10 and teachers proved the Japanese Theorem through the Carnot's Theorem. Third Part GeoGebra file and through iteration.

    History 11

    A lot of people (in Europe)- mostly students and a prof at university have worked on this "simple" problem. A trainee teacher in my school has started a tweed on twitter and a lot of people answered. He also made a proof (3 pages) and it will take some time to prepare a presentatation with all twitter answers and his own proof. We can be very curious of it! Monika (GER)

    History 12

    For interested teachers and older students: International conversation in Twitter started by a Trainee teacher at our School. There are two Proofs.

    History 11

    Monika, We can't wait to see the result! Norma Lisa Neiman