What can you say about these shapes? This problem challenges you to
create shapes with different areas and perimeters.
Identical squares of side one unit contain some circles shaded blue. In which of the four examples is the shaded area greatest?
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?
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.
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?
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
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. . . .
Can you find rectangles where the value of the area is the same as the value of the perimeter?
How many tiles do we need to tile these patios?
How many ways can you find of tiling the square patio, using square
tiles of different sizes?
How many centimetres of rope will I need to make another mat just
like the one I have here?
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.
The area of a square inscribed in a circle with a unit radius is,
satisfyingly, 2. What is the area of a regular hexagon inscribed in
a circle with a unit radius?
Can you help the children find the two triangles which have the
lengths of two sides numerically equal to their areas?
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?
If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
What fractions of the largest circle are the two shaded regions?
It's easy to work out the areas of most squares that we meet, but
what if they were tilted?
I'm thinking of a rectangle with an area of 24. What could its perimeter be?
What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?
Cut differently-sized square corners from a square piece of paper
to make boxes without lids. Do they all have the same volume?
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. . . .
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?
These practical challenges are all about making a 'tray' and covering it with paper.
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 thoughtful shepherd used bales of straw to protect the area
around his lambs. Explore how you can arrange the bales.
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 smallest number of tiles needed to tile this patio? Can
you investigate patios of different sizes?
At the corner of the cube circular arcs are drawn and the area enclosed shaded. What fraction of the surface area of the cube is shaded? Try working out the answer without recourse to pencil and. . . .
This practical challenge invites you to investigate the different
squares you can make on a square geoboard or pegboard.
These rectangles have been torn. How many squares did each one have
inside it before it was ripped?
What are the areas of these triangles? What do you notice? Can you generalise to other "families" of triangles?
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?
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?
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
An activity for high-attaining learners which involves making a new cylinder from a cardboard tube.
I cut this square into two different shapes. What can you say about
the relationship between them?
Explore this interactivity and see if you can work out what it
does. Could you use it to estimate the area of a shape?
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 the area of 'slices' cut off this cube of cheese. What
would happen if you had different-sized block of cheese to start
What happens to the area and volume of 2D and 3D shapes when you
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.
Can you maximise the area available to a grazing goat?
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 is the shape and dimensions of a box that will contain six cups and have as small a surface area as possible.
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. . . .