Changes
From Karnataka Open Educational Resources
688 bytes added
, 09:26, 12 August 2014
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| #Tanjents AP and AQ are drawn to circle with centre O, from an external point A. Prove that ∠PAQ=2.∠ OPQ <br> | | #Tanjents AP and AQ are drawn to circle with centre O, from an external point A. Prove that ∠PAQ=2.∠ OPQ <br> |
| [[File:fig1.png|200px]] | | [[File:fig1.png|200px]] |
| + | ===Interpretation of the problem=== |
| + | #O is the centre of the circle and tangents AP and AQ are drawn from an external point A. |
| + | #OP and OQ are the radii. |
| + | #The students have to prove thne angle PAQ=twise the angle OPQ. |
| + | ===Concepts used.=== |
| + | #The radii of a circle are equal. |
| + | #In any circle the radius drawn at the point of contact is perpendicular to the tangent. |
| + | #The tangent drawn from an external point to a circle a] are equal b] subtend equal angle at the centre c] are equally inclined to the line joining the centre and extrnal point. |
| + | #Properties of isoscles triangle. |
| + | #Properties of quadrillateral ( sum of all angles) is 360 degrees |
| + | #Sum of three angles of triangle is 180 degrees. |
| | | |
| == Ex 4.4.2== | | == Ex 4.4.2== |