Perimeters
On this page the activities look at developing understanding of perimeters of shapes.
In the first activity, what is the perimeter of the rectangle shown?
How many side lengths do you need to know to be able to calculate the perimeter of this rectangle? Click on lengths to get rid of them until you have the least number you need.
Why is this the minimum number of lengths you need?
In the first activity, what is the perimeter of the rectangle shown?
How many side lengths do you need to know to be able to calculate the perimeter of this rectangle? Click on lengths to get rid of them until you have the least number you need.
Why is this the minimum number of lengths you need?
Reset the activity using the refresh button in the top right corner of the activity.
Click on the "Hide all Lengths" button.
Press the "Square" button to make a square. How many lengths do you need to know to find the perimeter of a square?
Click on the sides you need, and calculate the perimeter. Check by showing all the lengths.
Click on the "Hide all Lengths" button.
Press the "Square" button to make a square. How many lengths do you need to know to find the perimeter of a square?
Click on the sides you need, and calculate the perimeter. Check by showing all the lengths.
Repeat the process above with other types of quadrilaterals using the buttons or making your own.
Make a list of which sides you need to know to calculate the perimeter for all types of quadrilateral.
Make a list of which sides you need to know to calculate the perimeter for all types of quadrilateral.
The below activity is the same as the one above, but for triangles.
For each type of triangle work out how many side lengths you need to know to calculate the perimeter.
Check this is the case by showing the sides you need.
For each type of triangle work out how many side lengths you need to know to calculate the perimeter.
Check this is the case by showing the sides you need.
What is a regular polygon?
How many side lengths do you need to calculate the perimeter of a regular polygon?
Predict the perimeter of each of the regular polygons with 4 sides up to 12 sides.
Use the activity below to check them by using the slider to change the number of sides.
Can you name all the polygons created?
How many side lengths do you need to calculate the perimeter of a regular polygon?
Predict the perimeter of each of the regular polygons with 4 sides up to 12 sides.
Use the activity below to check them by using the slider to change the number of sides.
Can you name all the polygons created?
Ideas for Teachers
All these activities are great for the students to explore themselves on a computer (perhaps as a homework), or for use in front of the class on the board. Before showing them the activity, you can start a discussion about what information they would need for different tyes of quadrilaterals/triangles. You can then show them the activity, and explore each one in turn. By doing this on the board, you can hide all the sides to start with, and ask them which sides they need to know, and get them to come and select which ones. You can also move the vertices of the shapes to create new shapes, and discuss these too.
The last activity looks at regular polygons (check their understanding or regular first), and asks them how many sides they need to know. They are then looking for a quick way to calculate the perimeter of a regular polygon, given one side length.
These activities can lead into a nice discussion of other shapes, and how many sides you need to know.
All these activities are great for the students to explore themselves on a computer (perhaps as a homework), or for use in front of the class on the board. Before showing them the activity, you can start a discussion about what information they would need for different tyes of quadrilaterals/triangles. You can then show them the activity, and explore each one in turn. By doing this on the board, you can hide all the sides to start with, and ask them which sides they need to know, and get them to come and select which ones. You can also move the vertices of the shapes to create new shapes, and discuss these too.
The last activity looks at regular polygons (check their understanding or regular first), and asks them how many sides they need to know. They are then looking for a quick way to calculate the perimeter of a regular polygon, given one side length.
These activities can lead into a nice discussion of other shapes, and how many sides you need to know.
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