# Maths GCSE: Geometry

Mathematician and comedian Matt Parker breaks down key GCSE angle problems into easy steps, including internal angles of polygons and bearings, to help students struggling to get a passing mark.

Looking at key GCSE Foundation angles topics, Matt emphasises the importance of not being intimidated by questions.

Looking at a multi-step problem, Matt encourages students to be confident and start somewhere.

The questions move through topics that are typical stumbling blocks for students, emphasizing, with graphics, methods to help remember key methods.

He also explores common misconceptions in dealing with these kinds of problems.

This short film is from the BBC series, The Maths Show.

### Teacher Notes

During the video:

• When the problem comes up on the screen involving isosceles and equilateral triangles, pause to ask your students to draw the situation and see how much they can fill in themselves before Matt speaks. It might be useful for students to have a copy of the question on a worksheet, or mini whiteboards for students to not fear making errors as they can just erase them.
• For the angles in a polygon section, students could look at the other polygons shown after the method and calculate the angles in hexagons, pentagons etc.
• Elicit responses from students regarding the direction of the bearing.

After the video:

• Explore other multi-step angle problems - put a large diagram on the board and encourage students to come to the board to label an angle. Encourage students to label any angle - not to worry about whether it is the answer required. Alternatively you could start with a simple diagram and slowly add to it, each time ask students to work out the new angles added.
• Look at the different approaches for irregular polygons and regular polygons - is using the exterior angle of a polygon (not covered in this video) method more useful with regular polygons? Would students remember to find the supplementary angle of the exterior angle for the interior angle? Could students use both methods to ensure they have the same answers? Students could make a poster or a video of a step by step guide of their preferred method.
• For bearings, students should look at bearing questions which you have to measure and those where you calculate. Bearings is a great topic for ‘spot the error’ exercises - ensure students are using the right numbers on a protractor, measuring clockwise from North and measuring the right direction (A from B not B from A for example).

### Curriculum Notes

Suitable for teaching maths at GCSE in England, Wales and Northern Ireland and National 4/5 or Higher in Scotland.