 Before we start, you should already know the equation of a circle. If you want a quick recap on that, watch this video first. The tangent is always perpendicular to the radius. This is a key piece of information for finding the equation of a tangent. We then just use our knowledge of the equation of a circle, the equation of a straight line, and the equation of tangents. Nothing new to learn. So let's jump straight in with an example. We know the centre is at 3, 2, and the tangent is at 6, negative 2. So we use this to find the gradient of the radius. If the gradient of the radius is minus 4 thirds, as the tangent is perpendicular to this, we can flip the gradient and change the sign. The equation of the tangent must be y equals 3 quarters x plus c. Then using the coordinates of the point on the circle, substitute x is 6 and y is negative 2 in to find the missing y intercept c value. So the equation of the tangent is y equals 3 quarters x minus 6.5. Nothing new to learn at all. Here's one for you to do. Pause the video, find the equation of tangent, and click play when you're ready. Did you get 4x plus 3y minus 32 equals 0? So that's all you need to know about tangents to circles. You just need to use the centre of the circle, the point of the tangent, and the knowledge that the tangent and the radius are always perpendicular. If you liked the video, give it a thumbs up, and don't forget to subscribe, comment below if you have any questions. Why not check out our Fuse school app as well? Until next time.