Can you work out the area of the inner square and give an explanation of how you did it?

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. . . .

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 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 this area?

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 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?

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. . . .

Arrange your fences to make the largest rectangular space you can. Try with four fences, then five, then six etc.

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?

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 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 total area of the four outside triangles which are outlined in red in this arrangement of squares inside each other?

What are the areas of these triangles? What do you notice? Can you generalise to other "families" of triangles?

What do these two triangles have in common? How are they related?

Choose a box and work out the smallest rectangle of paper needed to wrap it so that it is completely covered.

These practical challenges are all about making a 'tray' and covering it with paper.

It's easy to work out the areas of most squares that we meet, but what if they were tilted?

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?

Explore this interactivity and see if you can work out what it does. Could you use it to estimate the area of a shape?

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 into?

Prove that a triangle with sides of length 5, 5 and 6 has the same area as a triangle with sides of length 5, 5 and 8. Find other pairs of non-congruent isosceles triangles which have equal areas.

A task which depends on members of the group noticing the needs of others and responding.

Can you draw a square in which the perimeter is numerically equal to the area?

A follow-up activity to Tiles in the Garden.

A tower of squares is built inside a right angled isosceles triangle. The largest square stands on the hypotenuse. What fraction of the area of the triangle is covered by the series of squares?

What happens to the area and volume of 2D and 3D shapes when you enlarge them?

This article, written for teachers, discusses the merits of different kinds of resources: those which involve exploration and those which centre on calculation.

Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.

If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?

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.

An activity for high-attaining learners which involves making a new cylinder from a cardboard tube.

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?

Follow the instructions and you can take a rectangle, cut it into 4 pieces, discard two small triangles, put together the remaining two pieces and end up with a rectangle the same size. Try it!

Can you help the children find the two triangles which have the lengths of two sides numerically equal to their 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?

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.

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?

Investigate how this pattern of squares continues. You could measure lengths, areas and angles.

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?

How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?

Which is a better fit, a square peg in a round hole or a round peg in a square hole?

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 square carpet.

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. . . .

These rectangles have been torn. How many squares did each one have inside it before it was ripped?

Determine the total shaded area of the 'kissing triangles'.

What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?

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?