Triangles

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
Matching triangles

Age

5 to 7

Challenge level

Can you sort these triangles into three different families and explain how you did it?
problem
Wedge on wedge

Age

14 to 16

Challenge level

Two right-angled triangles are connected together as part of a structure. An object is dropped from the top of the green triangle where does it pass the base of the blue triangle?
problem
Fraction fascination

Age

7 to 11

Challenge level

This problem challenges you to work out what fraction of the whole area of these pictures is taken up by various shapes.
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
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
More transformations on a pegboard

Age

7 to 11

Challenge level

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

Age

5 to 7

Challenge level

How many different ways can you find to join three equilateral triangles together? Can you convince us that you have found them all?
problem
Half a triangle

Age

14 to 16

Challenge level

Construct a line parallel to one side of a triangle so that the triangle is divided into two equal areas.
problem
Triangle in a triangle

Age

14 to 16

Challenge level

Can you work out the fraction of the original triangle that is covered by the inner triangle?