This means that, using Pythagoras’ theorem, the equation of a circle with radius \(r\) and centre (0, 0) is given by the formula \(x^2+ y^2= r^2\). Example Find the equation of a circle with ...

Here's how this will work. You draw a circle. From that circle, you can determine both the circumference and the radius. Then the value of pi would be the circumference divided by twice the radius.

Sketch a diagram to show the circle and the tangent at the point (2, 4) labelling this P. Draw the radius from the centre of the circle to P. The tangent will have an equation in the form \(y = mx ...