maximum right angles

there are variations to the answers with the same maximum numbers of right angles
e.g. for the pentagon:

this task is interesting in that two patterns, for polygons with an odd number of sides and those with an even number of sides, seem evident

but then both break down...

the powerpoint for the task

David Fielker proposed and considered these tasks in his excellent series: 'Removing the shackles of Euclid'