## Saturday, 10 November 2012

### New Display - Year 10 work on missing angles

Here's my latest display put up this week in my classroom - replacing the TETRIS display as it was getting a bit 'mangled'.

The display is based around Mike Ollerton's idea in his book 'Getting the buggers to add up'. The lesson idea is to give each student a piece of coloured paper and to get them to make two folds in the piece of paper so that the fold intersect and aren't parallel with either of the sides of the original piece of paper. Then, the class work out how many angles they need to measure in order to then work out all other missing angles on the sheet. The students then were given protractors to measure angles on the sheet before then using these, and their existing knowledge of angle facts, to work out all other missing angles.
The class worked well on this and many of them then moved onto the extension activities:

Some of the class made 3 folds in their piece of paper and then measured an additional angle than previously having made and then worked out all remaining angles.

Some of the class even represented the 2 measured angles as alpha and beta and then wrote all other angles as expressions involving these angles i.e. 180 - alpha etc.

After the class had worked away on their 1st attempt I took suggestions from the class as to what angle facts they had used to work out the missing angles, suggestions included:

angles around a point = 360 degrees
angles on a straight line = 180 degrees
angles in a triangle = 180 degrees
angles in a quadrilateral = 360 degrees
opposite angles are equal
alternate angles are equal
the interior angles of a pentagon sum to 540 degrees (and then proof of this by splitting the pentagon into 3 triangles)
right angles = 90 degrees

In addition this also ensured that the class were able to measure angles accurately using a protractor and to estimate the values of angles to check their workings - what type of angles they were too (obtuse, acute, reflex).

This was great in terms of ensuring the class' previous knowledge was put into an interesting activity that engaged them and used all their prior knowledge and thinking skills to solve. It also allowed me to build in a bit of algebra to the task that we had also covered recently.

Here are some of the finished pieces of work up on my new display (on the right, next to my year 9's Pi-em h/w - see previous post)