Skip over navigation
How many triples of points are there where all three lie on a straight line (not necessarily equally spaced)?
If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.
Gridlines
Age 14 to 16
ShortChallenge Level 
There are lots of ways of choosing three dots from this $4$ by $4$ array.
How many triples of points are there where all three lie on a straight line (not necessarily equally spaced)?
If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.
This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.
You may also like
Instant Insanity
Given the nets of 4 cubes with the faces coloured in 4 colours, build a tower so that on each vertical wall no colour is repeated, that is all 4 colours appear.
Magic Caterpillars
Label the joints and legs of these graph theory caterpillars so that the vertex sums are all equal.
