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.
A simple visual exploration into halving and doubling.
This article for teachers gives some food for thought when teaching
ideas about area.
Look at the mathematics that is all around us - this circular
window is a wonderful example.
Grandpa was measuring a rug using yards, feet and inches. Can you
help William to work out its area?
How would you move the bands on the pegboard to alter these shapes?
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?
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?
Use the information on these cards to draw the shape that is being described.
What can you say about these shapes? This problem challenges you to
create shapes with different areas and perimeters.
A thoughtful shepherd used bales of straw to protect the area
around his lambs. Explore how you can arrange the bales.
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. . . .
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
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?
If I use 12 green tiles to represent my lawn, how many different
ways could I arrange them? How many border tiles would I need each
Can you draw a square in which the perimeter is numerically equal
to the area?
Arrange your fences to make the largest rectangular space you can. Try with four fences, then five, then six etc.
How many ways can you find of tiling the square patio, using square
tiles of different sizes?
This practical challenge invites you to investigate the different
squares you can make on a square geoboard or pegboard.
What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?
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 is the smallest number of tiles needed to tile this patio? Can
you investigate patios of different sizes?
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
Can you work out the area of the inner square and give an
explanation of how you did it?
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?
Nine squares with side lengths 1, 4, 7, 8, 9, 10, 14, 15, and 18 cm can be fitted together to form a rectangle. What are the dimensions of the rectangle?
These rectangles have been torn. How many squares did each one have
inside it before it was ripped?
An investigation that gives you the opportunity to make and justify
Polygons drawn on square dotty paper have dots on their perimeter
(p) and often internal (i) ones as well. Find a relationship
between p, i and the area of the polygons.
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?
What is the total area of the four outside triangles which are
outlined in red in this arrangement of squares inside each other?
Points P, Q, R and S each divide the sides AB, BC, CD and DA respectively in the ratio of 2 : 1. Join the points. What is the area of the parallelogram PQRS in relation to the original rectangle?
It's easy to work out the areas of most squares that we meet, but
what if they were tilted?
Can you help the children find the two triangles which have the
lengths of two sides numerically equal to their areas?
Explore one of these five pictures.
If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?
A follow-up activity to Tiles in the Garden.
Cut differently-sized square corners from a square piece of paper
to make boxes without lids. Do they all have the same volume?
Can you find rectangles where the value of the area is the same as the value of the perimeter?
These practical challenges are all about making a 'tray' and covering it with paper.
I cut this square into two different shapes. What can you say about
the relationship between them?
How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?
How can you change the area of a shape but keep its perimeter the same? How can you change the perimeter but keep the area the same?
A circle with the radius of 2.2 centimetres is drawn touching the sides of a square. What area of the square is NOT covered by the circle?
Use the interactivity to find all the different right-angled
triangles you can make by just moving one corner of the starting
Investigate how this pattern of squares continues. You could
measure lengths, areas and angles.
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?
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?