Question 1117484
<font face="Times New Roman" size="+2">


The tangent has to be perpendicular to the radius at the point of tangency, and since the chord is parallel to the tangent, the chord is perpendicular to the radius.  Therefore the radius bisects the chord, and, in this case it is given that the chord bisects the radius. See http://www.dentonisd.org/cms/lib/TX21000245/Centricity/Domain/926/Circle%20Theorems.pdf


Construct a radius to one endpoint of the chord.  This forms a right triangle with sides of 15 and *[tex \Large \frac{r}{2}] and a hypotenuse of *[tex \Large r].  Use Pythagoras to set up an equation in *[tex \Large r] and solve.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
<img src="http://c0rk.blogs.com/gr0undzer0/darwin-fish.jpg">
*[tex \Large \ \
*[tex \LARGE \ \ \ \ \ \ \ \ \ \  

</font>