If the line is tangent to circle at point A and the radius ( suppose AO) has a slope of 2.5 then a slope of the tangent line is : [tex] \frac{-1}{2.5}= -0.4 [/tex] Explanation: The product of slopes of two perpendicular lines is -1. To get second slope we have to divide -1 by the first one. Answer:C) - 0.4
