Tangents drawn from an External Point

 

 Tangents drawn from an External Point

Objective
To verify experimentally that lengths of tangents drawn from an external point to a circle are equal.

Tangent
A line touching the circle at a point is called a tangent to the circle.

Prerequisite Knowledge

1. Tangent to a circle.
2. Length of a tangent.
   

Materials Required
Glazed papers, a white chart paper, sketch pens, a pair of scissors, geometry box, fevicol.

Procedure

1. Cut a circle of any radius from a glazed paper and paste it on a white chart paper.
   
2. Take any point P on the circle.
   
3. From P, fold the paper in such a way that it just touches the circle at P. Press it and unfold to get a tangent PA.
   
4. From A, fold the paper to get tangent AQ.
   
5. Fold the circle along OA.
6. Join OP, OA, OQ.
   

Observation
Students observe that point P coincide with Q
∴ AP = AQ

Result
Thus it is verified that lengths of tangents drawn from an external point to a circle are equal.