A line is tangent to a circle at the point (2, 5). A parallel line is tangent to the circle at (8, 13). What is the common slope of the two lines? Express your answer as a common fraction.
To find the slope, we use our trusty formula- y2−y1x2−x1
Plugging in the values, we have:13−58−2=86=43
But since the two tangents lines are perpendicular to this diameter and have a slope equal to the negative reciprocal of the diameter’s slope, we have −34
+818 
