O is the centre of a circle of radius 8 cm. The tangent at a point A on the circle cuts a line through O at B such that AB = 15 cm. Find OB.

Fill in the blanks:

(i) The common point of a tangent and the circle is called………… .

(ii) A circle may have ………… parallel tangents.

(iii) A tangent to a circle intersects it in ……… points(s).

(iv) A line intersecting a circle in two points is called a ………… .

(v) The angle between tangent at a point on a circle and the radius through the point is ………… .

How many tangents can a circle have?

If the tangent at a point P to a circle with centre O cuts a line through O at Q such that PQ = 24 cm and OQ = 25 cm. Find the radius of the circle.

If PT is a tangent at T to a circle whose centre is O and OP = 17 cm, OT = 8 cm, find the length of the tangent segment PT.