## Reasoning in Geometry

07/28/2010

We are currently learning Angles, Triangles and Quadrilaterals. More to the point, we are learning about using what we know (facts) to convey our thinking (reasoning) through reading, writing and speaking (language).

Most of the facts and language used for reasoning have been learned in year 7. This year, the focus is on putting it all together.

For example, students already know of the 90, 180 and 360 degree angles. They know these are called right, straight, and revolution angles respectively. They know the symbols for these as well. This allows them to reason that adjacent angles are complementary or supplementary or at a point.

Here's a list of the language we use:
• angles at a point
• vertically opposite angles
• corresponding angles, || lines
• alternate angles, || lines
• co-interior angles, || lines
• angle sum of a triangle
• exterior angle of a triangle
• equal sides of an isosceles (or equilateral) triangle
• equal angles of an isosceles (or equilateral) triangle
• angle sum of a quadrilateral

## Author

I am the 8MATE2010 teacher as well as an ICT integrator. I use technology to facilitate learning with a social bent and realistic context, where possible.

Mrs Mawby