# Geometrical Proof with Vectors

Students learn how to use vector notation to prove geometrical facts about 2D shapes.  Throughout the lesson students identify and prove parallel lines, parallelograms and trapezia using vector notation.  This lesson comes with a vectors worksheet.  The start of the lesson is used to review using vector addition and subtraction to define the geometrical properties of polygons.
##### Differentiated Learning Objectives
• All students should be able to use the geometrical properties of polygons to define vectors.
• Most students should be able to prove the geometrical properties of polygons using vectors.
• Some students should be able to use ratio and the geometrical properties of polygons to prove two lines are parallel.

### Mr Mathematics Blog

#### Trigonometric Identities Sin, Cos and Tan

How to introduce the sin, cos and tan trigonometric identities.

#### Calculating a Reverse Percentage

How to teach calculating the original amount after a percentage change.

#### Comparing Datasets using the Mean and Range

The importance of the range when comparing comparing datasets.