This type of activity is known as Demonstration. Please read the guidance notes here, where you will find useful information for running these types of activities with your students.

1. Demonstration

• I display the Geogebra page in silence with all information revealed
• I ask students to pause and reflect on what the page shows
• I then hide the perimeter calculation on the second diagram and then move Point E
• I ask students to reflect on what has changed and predict what will happen when I reveal the size of the perimeter
• I continue the process, always changing one thing from the original diagram, and always giving students an opportunity to pause, reflect and predict
• At the end I ask students to discuss the rule with their partners, and then we have a class discussion

2. Possible variations

• Vary the position of each point
• Create two different rectangles with the same perimeter

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