Rashmi Kathuria’s Hands on Math class mathclass_khms@yahoo.co.in
Aim: By paper folding, cutting and pasting verify “Lengths of tangents drawn from an external point to a circle are equal". Material Required: Colored paper, scissors, geometry box, thread, glue Procedure: Step 1 Draw a circle of any radius on a colored paper and cut it.
Step 2 Take a rectangular sheet of paper and paste the circle cut out on it. Let O be the centre of the circle
mathclass_khms@yahoo.co.in
Rashmi Kathuria’s Hands on Math class mathclass_khms@yahoo.co.in
Step 3 Mark a point P outside the circle.
Step 4 Fold the rectangular sheet in such a way that it passes through P and touches the circle at a point.
mathclass_khms@yahoo.co.in
Rashmi Kathuria’s Hands on Math class mathclass_khms@yahoo.co.in
Step 5 On the crease, draw a tangent to the circle PA, where A is point of contact. Similarly get another tangent PB.
Step 6 Take a thread and paste its corner on P and cut the thread of length PA.
mathclass_khms@yahoo.co.in
Rashmi Kathuria’s Hands on Math class mathclass_khms@yahoo.co.in
Step 7 Put the thread of length PA on PB.
Observations The thread covering PA completely covers PB. PA and PB are tangents of a circle. Result The lengths of tangents drawn from an external point to a circle are equal.
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