This means that, using Pythagoras’ theorem, the equation of a ... line that touches the circle at P. The tangent is perpendicular to the radius which joins the centre of the circle to the ...

To find the gradient use the fact that the tangent is perpendicular to the radius from the point it meets the circle. Work out the gradient of the radius (CP) at the point the tangent meets the ...

The world of geometry just witnessed a pivotal breakthrough. Mathematicians at Monash University have cracked a centuries-old puzzle dating back to the 17th century, extending Descartes’ Circle ...