Draw a circle of radius 6 cm. From a point 10 cm away from its centre, construct the pair of tangents to the circle and measure their lengths.


Steps of Construction:


Step I: With O as a centre and radius equal to 6 cm, a circle is drawn.


Step II: A point P at a distance of 10 cm from the centre O is taken. OP is joined.


Step III: Perpendicular bisector OP is drawn and let it intersected at M.


Step IV: With M as a centre and OM as a radius, a circle is drawn intersecting previous circle at Q and R.


Step V: PQ and PR are joined.


Thus, PQ and PR are the tangents to the circle.


On measuring the length, tangents are equal to 8 cm.


PQ = PR = 8cm.


Justification:


OQ is joined.


PQO = 90° (Angle in the semi circle)


OQ PQ


Therefore, OQ is the radius of the circle then PQ has to be a tangent of the circle.


Similarly, PR is a tangent of the circle


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