The diagram shows line with equation y+2x=2y + 2x = 2y+2x=2 which is a tangent to a circle with centre (9,−1)(9, -1)(9,−1).
Find an equation for the circle, giving the radius in exact form.
292 exam-style questions on Edexcel A Level Maths Circles, covering 6.1 Midpoints and Perpendicular Bisectors, 6.2 Equation of a Circle, 6.3 Intersections of Straight Lines and Circles, 6.4 Use Tangent and Chord Properties, and 6.5 Circles and Triangles. Each one has a worked solution and a mark scheme showing where the marks go.