Maths - Triangles in a Co-ordinate System
Pearson Edexcel Mathematics 2022
Starting a co-ordinate triangle problem
When working with triangles in a co-ordinate system, the most important step is?
Drawing a sketch.
Proving a right-angled triangle
How can you prove that a triangle is right-angled in a co-ordinate system?
Find the gradients of the lines and prove two are perpendicular.
How can you prove two lines are perpendicular?
Show their gradients multiply to give $-1$.
Proving an isosceles triangle
How can you prove that a triangle is isosceles in a co-ordinate system?
Show _ two _ lines have the same length.
What step is often forgotten in proving a triangle is isosceles in a co-ordinate system?
Not showing that there is at least one length different from the other two, otherwise it would be equilateral.
Length notation
What does the notation $ \vert AB \vert $ represent in terms of co-ordinate systems?
The length of line $AB$.