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?
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?
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
These rectangles have been torn. How many squares did each one have
inside it before it was ripped?
Can you help the children find the two triangles which have the
lengths of two sides numerically equal to their areas?
Can you draw a square in which the perimeter is numerically equal
to the area?
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.
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?
What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?
These practical challenges are all about making a 'tray' and covering it with paper.
What is the smallest number of tiles needed to tile this patio? Can
you investigate patios of different sizes?
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?
A thoughtful shepherd used bales of straw to protect the area
around his lambs. Explore how you can arrange the bales.
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 can you say about these shapes? This problem challenges you to create shapes with different areas and perimeters.
An investigation that gives you the opportunity to make and justify
How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?
If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?
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.
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?
It's easy to work out the areas of most squares that we meet, but
what if they were tilted?
Investigate the area of 'slices' cut off this cube of cheese. What
would happen if you had different-sized block of cheese to start
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
Arrange your fences to make the largest rectangular space you can. Try with four fences, then five, then six etc.
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.
What do these two triangles have in common? How are they related?
I cut this square into two different shapes. What can you say about
the relationship between them?
Explore one of these five pictures.
What are the areas of these triangles? What do you notice? Can you generalise to other "families" of triangles?
A follow-up activity to Tiles in the Garden.
How many centimetres of rope will I need to make another mat just
like the one I have here?
How many tiles do we need to tile these patios?
Here are many ideas for you to investigate - all linked with the
Explore this interactivity and see if you can work out what it
does. Could you use it to estimate the area of a shape?
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?
What is the total area of the four outside triangles which are
outlined in red in this arrangement of squares inside each other?
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
Grandpa was measuring a rug using yards, feet and inches. Can you
help William to work out its area?
A simple visual exploration into halving and doubling.
Use the information on these cards to draw the shape that is being described.
Look at the mathematics that is all around us - this circular
window is a wonderful example.
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.
This article for teachers gives some food for thought when teaching
ideas about area.
Can you maximise the area available to a grazing goat?
How would you move the bands on the pegboard to alter these shapes?
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. . . .
A red square and a blue square overlap so that the corner of the red square rests on the centre of the blue square. Show that, whatever the orientation of the red square, it covers a quarter of the. . . .
Can you find a general rule for finding the areas of equilateral triangles drawn on an isometric grid?