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