In the figure above, a circle with center (-5, 2) passes through the point (-1, 1). Line l, not shown, is tangent to the circle at (-1, 1). What is the y-intercept of line l ?



Comments (2)

Darn it! the signs got me adding -1 and -5, but I could have used the corner of a sheet of paper which is square with perpendicular lines to determine the intercept as a no brainer — line up the center (-5,2) and the tangential point (-1,1 )on one edge of the paper then project other edge to the intercept.

This time I did the paper trick and it still came out at 4 which is wrong. yes the best way ius to know that tangents are perpendicular to radii and that the inverse negative is the slope of a perpendicular line.

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