Step 1: Recall the tangent properties

            NOTE: Tangent is perpendicular to the radius at the point of

            contact(tangency)

            EXAMPLE: Here PA is tangent segment and OA is radius of circle.

Step 3: Remember the Pythagoras theorem to find the unknown length

            NOTE: We can form a right angle triangle by adding the centre and the end

            point of the tangent

              (Pythagoras theorem)   side^2 + side^2 = (hypotenuse)^2

Step 4: Substitute given values in the Pythagoras theorem and simplify the

            equation.

          EXAMPLE:   OP^2 = OA^2 + PA^2 (Pythagoras theorem)

                              10^2 = 6^2 + PA^2

                              100 = 36 + PA^2

                               PA^2 = 100 - 36 = 64

                                    ∴ PA = 64 = 8 cm