### The Best Square

How would you judge a competition to draw a freehand square?

### Trig-trig

Explore the properties of combinations of trig functions in this open investigation.

### Chance of That

What's the chance of a pair of lists of numbers having sample correlation exactly equal to zero?

# Few and Far Between?

##### Age 16 to 18Challenge Level

This open investigation follows on from the problem Generating Triples. It can be taken to many levels of complexity.

The well-known Pythagorean Triple ${3,4,5}$ has the property that the two smaller numbers differ by 1.

Can you find any more Pythagorean Triples where the two smaller numbers differ by 1? Investigate your findings.

For more investigations see our Stage 5 pages.