What are the areas of these triangles? What do you notice? Can you generalise to other "families" of triangles?
Can you maximise the area available to a grazing goat?
Semicircles are drawn on the sides of a rectangle ABCD. A circle passing through points ABCD carves out four crescent-shaped regions. Prove that the sum of the areas of the four crescents is equal to. . . .
If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?
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. . . .
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
It's easy to work out the areas of most squares that we meet, but
what if they were tilted?
How many centimetres of rope will I need to make another mat just
like the one I have here?
An investigation that gives you the opportunity to make and justify
Can you draw a square in which the perimeter is numerically equal
to the 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?
I'm thinking of a rectangle with an area of 24. What could its perimeter be?
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?
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. . . .
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. . . .
How many ways can you find of tiling the square patio, using square
tiles of different sizes?
These practical challenges are all about making a 'tray' and covering it with paper.
A hallway floor is tiled and each tile is one foot square. Given
that the number of tiles around the perimeter is EXACTLY half the
total number of tiles, find the possible dimensions of the hallway.
Choose a box and work out the smallest rectangle of paper needed to
wrap it so that it is completely covered.
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
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?
What can you say about these shapes? This problem challenges you to create shapes with different areas and perimeters.
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?
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?
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?
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
Can you help the children find the two triangles which have the
lengths of two sides numerically equal to their areas?
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. . . .
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?
These rectangles have been torn. How many squares did each one have
inside it before it was ripped?
You can move the 4 pieces of the jigsaw and fit them into both
outlines. Explain what has happened to the missing one unit of
Can you work out the area of the inner square and give an
explanation of how you did it?
Determine the total shaded area of the 'kissing triangles'.
This practical challenge invites you to investigate the different
squares you can make on a square geoboard or pegboard.
Is it possible to remove ten unit cubes from a 3 by 3 by 3 cube made from 27 unit cubes so that the surface area of the remaining solid is the same as the surface area of the original 3 by 3 by 3. . . .
Can you find rectangles where the value of the area is the same as the value of the perimeter?
What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?
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.
What is the smallest number of tiles needed to tile this patio? Can
you investigate patios of different sizes?
Identical squares of side one unit contain some circles shaded blue. In which of the four examples is the shaded area greatest?
Cut differently-sized square corners from a square piece of paper
to make boxes without lids. Do they all have the same volume?
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 thoughtful shepherd used bales of straw to protect the area
around his lambs. Explore how you can arrange the bales.
You have a 12 by 9 foot carpet with an 8 by 1 foot hole exactly in
the middle. Cut the carpet into two pieces to make a 10 by 10 foot
An activity for high-attaining learners which involves making a new cylinder from a cardboard tube.
Derive a formula for finding the area of any kite.
A task which depends on members of the group noticing the needs of
others and responding.
Explore this interactivity and see if you can work out what it
does. Could you use it to estimate the area of a shape?
What happens to the area and volume of 2D and 3D shapes when you