Triangles

problem

Inside Seven Squares

Age

7 to 11

Challenge level

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

Timber!

Age

7 to 11

Challenge level

How can the school caretaker be sure that the tree would miss the school buildings if it fell?
problem

Tessellating Transformations

Age

7 to 11

Challenge level

Can you find out how the 6-triangle shape is transformed in these tessellations? Will the tessellations go on for ever? Why or why not?
problem

Number the Sides

Age

7 to 11

Challenge level

The triangles in these sets are similar - can you work out the lengths of the sides which have question marks?
problem

Triangle Island

Age

7 to 11

Challenge level

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?
problem

Uncanny Triangles

Age

7 to 11

Challenge level

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

Cartesian Isometric

Age

7 to 11

Challenge level

The graph below is an oblique coordinate system based on 60 degree angles. It was drawn on isometric paper. What kinds of triangles do these points form?
problem

Triangle Pin-Down

Age

7 to 11

Challenge level

Use the interactivity to investigate what kinds of triangles can be drawn on peg boards with different numbers of pegs.
problem

Sticks and Triangles

Age

7 to 11

Challenge level

Using different numbers of sticks, how many different triangles are you able to make? Can you make any rules about the numbers of sticks that make the most triangles?
problem

Triangle Transformation

Age

7 to 14

Challenge level

Start with a triangle. Can you cut it up to make a rectangle?