• THE Circle has a centre O.AM&BM are the tangents.show that : O,A,B,M ARE CONCYCLIC
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  • IF THE RADII OF TWO CONCENTRIC CIRCLES ARE 15cm &  17cm show that:the length of the one chord which  is tangent to the other.
 
 

Asked by aninadathoorsridharan | 11th Nov, 2016, 06:53: PM

Expert Answer:

 
(ii) begin mathsize 16px style The space question space doesn apostrophe straight t space seem space to space be space correct comma space but space straight I space am space assuming space we space have space to space find space
the space length space of space the space tangent space to space the space smaller space circle.
Let space us space call space that space tangent space straight x.
In space increment OPA comma space OP perpendicular straight x comma space since space perpendicular space from space the space centre space to space the space chord space bisects space the space chord.
So comma space by space the space Pythagoras space theorem comma
AO squared space equals space OP squared space plus thin space AP squared
rightwards double arrow 17 squared space equals space 15 squared space plus thin space AP squared
rightwards double arrow AP squared space equals space 289 space minus space 225 space equals space 64
rightwards double arrow AP space equals space 8 space cm
Since space straight x space is space the space chord space to space the space larger space circle comma space OP perpendicular straight x space and space OP space bisects space straight x
So comma space straight x space equals space 2 AP space equals space 2 left parenthesis 8 right parenthesis space equals space 16 space cm
So comma space the space tangent space to space the space circle space is space 16 space cm.

Kindly space post space only space one space query space at space straight a space time space please. end style

Answered by Rebecca Fernandes | 12th Nov, 2016, 08:59: AM

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