Finding the endpoint when given a midpoint

Finding the endpoint of a line segment when the midpoint is given is a useful skill in geometry and coordinate geometry. It often arises in tasks like map plotting or computer graphics when you're determining symmetry or completing shapes. By using simple algebraic formulas, you can calculate the endpoint that balances the midpoint perfectly between the two points. Jump to the questions

Practise now

Given one endpoint (blue) and the midpoint (red), enter the coordinates of the other endpoint. Remember to include brackets in your answer!