Question 1190323
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<pre>

If O is the center of the circle, them OTK is a right angle triangle.


THEREFORE,  TK = {{{sqrt(TO^2-OK^2)}}} = {{{sqrt(89^2-39^2)}}} = {{{sqrt(6400)}}} = 80  units.    <U>ANSWER</U>


Notice that 39 = 78/2 is the radius of the circle.
</pre>

Solved.


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If you want to learn more about tangent lines to circles, &nbsp;look into the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Circles/A-tangent-line-to-a-circle-is-perpendicular-to-the-radius-drawn-to-the-tangent-point.lesson>A tangent line to a circle is perpendicular to the radius drawn to the tangent point</A>, 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Circles/Tangent-segments-to-a-circle-from-a-point-outside-the-circle.lesson>Tangent segments to a circle from a point outside the circle</A>, 

in this site.