To find the equation of a circle when you know the radius and centre, use the formula \({(x - a)^2} + {(y - b)^2} = {r^2}\), where \((a,b)\) represents the centre of the circle, and \(r\) is the ...

A tangent to a circle at point P is a straight line that touches the circle at P. The tangent is perpendicular to the radius which joins the centre of the circle to the point P. As the tangent is a ...

A strange 300-foot pattern of circles and lines recently appeared in a farmer's field in the English countryside near Wiltshire, a place long associated with mysteries such as crop circles and ...