CBSE Class 10 Maths Circles

in the given figure a triangle abc is drawn to circumscribe a circle of radius 3 cm such that the segment bd and dc are respectively of length 6 and 9 cm
if the area of traingle abc is 54cm2 then find side ab and ac
 prime factorisation
 prove that the tangent at any point of a circle is perpendicular to the radius through the point of contact
 radious of circle is
 A tangent PQ at a point P on a circle of radius 5cm meets a line through the centre O at a point such that OQ=13cm. Find the length of PQ.
 Prove that the lengths of tangents drawn from an external point to a circle are equal. *
 The length of a tangent from a point A at distance 5 cm from the centre of the circle is 4 cm. The radius of the circle is
 From any point on the common chord of two intersecting circles, tangents be drawn to thecircles, prove that they are equal.

please answer these questions
 A tangent PA is drawn fron an external point P to a circle of radius 3 cm such that the distance of the point P from O is 6cm.Find yhe value of.