5. Prove that the perpendicular at the point of contact to the tangent to a circle passes through the centre.
In the above figure, the line AXB is the tangent to a circle with centre O. Here, OX is the perpendicular to the tangent AXB () at point of contact X.
Therefore, we have,
BXO + YXB =
OXY is a collinear
OX is passing through the centre of the circle.