Question 728953
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If the circle is centered at the origin, the radius is the distance from the origin to the given point.  Then the diameter is 2 times the radius.  Use the distance formula to find the radius:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ d\ =\ sqrt{(x_1\ -\ x_2)^2\ +\ (y_1\ -\ y_2)^2}]


where *[tex \Large \left(x_1,y_1\right)] and *[tex \Large \left(x_2,y_2\right)] are the coordinates of the given points. Hint:  The origin is the point *[tex \LARGE (0,\,0)]


By the way, given the precision implied by the coordinates of the given point, it is truly inappropriate to expect the answer to be precise to two decimal places.  If the instructor wanted the answer to the nearest hundreth, s/he should have specified the origin at *[tex \LARGE (0.00,\,0.00)] and the point on the circle as *[tex \LARGE (-4.00,\,-2.00)].  You should never report an approximation based on measurements to a greater precision than the least precise given measurement.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
<font face="Math1" size="+2">Egw to Beta kai to Sigma</font>
My calculator said it, I believe it, that settles it
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