#### Home / Interactive Lessons / Algebra / GCSE / Year 9 Term 3

The start of the lesson is used to recap calculating the equation of straight line graphs.  The development phase teaches students how to calculate the gradient of perpendicular functions.  As learning progress they are challenged to derive the equation of perpendicular graphs.
##### Differentiated Learning Objectives
• All students should be able to calculate the gradient of perpendicular lines.
• Most students should be able to calculate the equation of a perpendicular line.
• Some students should be able to calculate the equation of lines in the form ax + by + c = 0.

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