Steps of construction :
(i) Draw a chord PQ through the given point on the circle.
(ii) Take a point R on the circle and join P and Q to a point R.
(iii) Construct ∠QPY = ∠PRQ on the opposite sides of the chord PQ.
(iv) Produce YP to X’ to get YPX as the required tangent.
Construct a tangent to the circle from an external point:
In this section we shall study the construction at tangent to a circle from an external point when its center is ; (i)Known (ii)Unknown
Type (Ii). Contruction at tangent to a circle from an external point when its centre is known.
Steps of construction :
(i) Join the centre O of the circle to the given external point P i.e., join OP.
(ii) Draw right bisector of OP, intersecting OP at Q.
(iii) Taking Q as centre and OQ = PQ as radius, draw a circle to intersect the given circle at T and T’.
(iv) Join PT and PT’ to get the required tangents as PT and PT’.