Inside Triangles

Stage: 1 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Here is a four by four dotty grid:

four by four dotty grid

I have joined three dots on the grid to make a triangle which has one dot inside it:

triangle with one dot inside

How many different triangles with one dot in the middle can you draw?

How do you know have found them all?

You may like to experiment with the pegboard interactivity below, or you could print off this page of dotty grids to work on.

Full Screen Version

This text is usually replaced by the Flash movie.

Published June 2007,July 2011,August 2011.