A task which depends on members of the group noticing the needs of
others and responding.
You have pitched your tent (the red triangle) on an island. Can you
move it to the position shown by the purple triangle making sure
you obey the rules?
Determine the total shaded area of the 'kissing triangles'.
Explore this interactivity and see if you can work out what it
does. Could you use it to estimate the area of a shape?
Can you draw a square in which the perimeter is numerically equal
to the area?
A simple visual exploration into halving and doubling.
I cut this square into two different shapes. What can you say about
the relationship between them?
Can you help the children find the two triangles which have the
lengths of two sides numerically equal to their areas?
Have a good look at these images. Can you describe what is happening? There are plenty more images like this on NRICH's Exploring Squares CD.
If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?
Draw some isosceles triangles with an area of $9$cm$^2$ and a vertex at (20,20). If all the vertices must have whole number coordinates, how many is it possible to draw?
What do these two triangles have in common? How are they related?
This article for teachers gives some food for thought when teaching
ideas about area.
What shape has Harry drawn on this clock face? Can you find its
area? What is the largest number of square tiles that could cover
What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?
What happens to the area of a square if you double the length of
the sides? Try the same thing with rectangles, diamonds and other
shapes. How do the four smaller ones fit into the larger one?
Read about David Hilbert who proved that any polygon could be cut up into a certain number of pieces that could be put back together to form any other polygon of equal area.
How many centimetres of rope will I need to make another mat just
like the one I have here?
What is the total area of the four outside triangles which are
outlined in red in this arrangement of squares inside each other?
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
Grandpa was measuring a rug using yards, feet and inches. Can you
help William to work out its area?
In this game for two players, you throw two dice and find the product. How many shapes can you draw on the grid which have that area or perimeter?
What can you say about these shapes? This problem challenges you to
create shapes with different areas and perimeters.
These pictures were made by starting with a square, finding the
half-way point on each side and joining those points up. You could
investigate your own starting shape.
Explore one of these five pictures.
A follow-up activity to Tiles in the Garden.
What is the largest number of circles we can fit into the frame
without them overlapping? How do you know? What will happen if you
try the other shapes?
What happens to the area and volume of 2D and 3D shapes when you
These practical challenges are all about making a 'tray' and covering it with paper.
Look at the mathematics that is all around us - this circular
window is a wonderful example.
An investigation that gives you the opportunity to make and justify
Arrange your fences to make the largest rectangular space you can. Try with four fences, then five, then six etc.
My local DIY shop calculates the price of its windows according to the area of glass and the length of frame used. Can you work out how they arrived at these prices?
Use the information on these cards to draw the shape that is being described.
How would you move the bands on the pegboard to alter these shapes?
This rectangle is cut into five pieces which fit exactly into a triangular outline and also into a square outline where the triangle, the rectangle and the square have equal areas.
Derive a formula for finding the area of any kite.
Do you know how to find the area of a triangle? You can count the
squares. What happens if we turn the triangle on end? Press the
button and see. Try counting the number of units in the triangle
now. . . .
This practical challenge invites you to investigate the different
squares you can make on a square geoboard or pegboard.
It is possible to dissect any square into smaller squares. What is
the minimum number of squares a 13 by 13 square can be dissected
What are the areas of these triangles? What do you notice? Can you generalise to other "families" of triangles?
Seven small rectangular pictures have one inch wide frames. The
frames are removed and the pictures are fitted together like a
jigsaw to make a rectangle of length 12 inches. Find the dimensions
of. . . .
These rectangles have been torn. How many squares did each one have
inside it before it was ripped?
Choose a box and work out the smallest rectangle of paper needed to
wrap it so that it is completely covered.
How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?
Make an eight by eight square, the layout is the same as a
chessboard. You can print out and use the square below. What is the
area of the square? Divide the square in the way shown by the red
dashed. . . .
What is the smallest number of tiles needed to tile this patio? Can
you investigate patios of different sizes?
How many ways can you find of tiling the square patio, using square
tiles of different sizes?
Cut differently-sized square corners from a square piece of paper
to make boxes without lids. Do they all have the same volume?
Investigate all the different squares you can make on this 5 by 5
grid by making your starting side go from the bottom left hand
point. Can you find out the areas of all these squares?