Triangles

problem

Triangle Pin-Down

Age

7 to 11

Challenge level

3 out of 3

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

3 out of 3

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

1 out of 3

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

Threesomes

Age

11 to 14

Challenge level

1 out of 3

Imagine an infinitely large sheet of square dotty paper on which you can draw triangles of any size you wish (providing each vertex is on a dot). What areas is it/is it not possible to draw?
problem

Dotty Triangles

Age

11 to 14

Challenge level

1 out of 3

Imagine an infinitely large sheet of square dotty paper on which you can draw triangles of any size you wish (providing each vertex is on a dot). What areas is it/is it not possible to draw?
problem

Isosceles Meld

Age

11 to 14

Challenge level

1 out of 3

Weekly Problem 9 - 2012
What is the angle QPT in this diagram?
problem

Stellar Angles

Age

11 to 14

Challenge level

1 out of 3

Weekly Problem 30 - 2013
What is the angle $x$ in the star shape shown?
problem

Notes on a Triangle

Age

11 to 14

Challenge level

1 out of 3

Can you describe what happens in this film?
problem

Triangular Tantaliser

Age

11 to 14

Challenge level

2 out of 3

Draw all the possible distinct triangles on a 4 × 4 dotty grid. Convince me that you have all possible triangles.
problem

Isosceles

Age

11 to 14

Challenge level

3 out of 3

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.