M - Pure 1 - 6) Circles

Question 1

Equation of a circle with centre (a, b) and radius r

Answer 1

(x - a)² + (y - b)² = r²

Question 2

Part of a circle that the perpendicular bisector of a chord goes through

Answer 2

Goes through the centre of the circle

Question 3

Method to find the centre of a circle from any 3 points on its circumference

Answer 3

1. Find equations of the perpendicular bisectors of two different chords
2. Find coordinates of their intersection