Multiple choice general knowledge math & puzzles

The perpendicular bisector of the line segment joining P (1, 4) and Q (k, 3) has y-intercept - 4. Then a possible value of k is

  1. 1

  2. -4

  3. 3

  4. 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Midpoint is ((1+k)/2, 7/2). Slope PQ is -1/(k-1). Perpendicular slope is (k-1). Line: y - 7/2 = (k-1)(x - (1+k)/2). Y-intercept (x=0): -4 - 7/2 = (k-1)(-(1+k)/2) => -15/2 = -(k^2-1)/2 => 15 = k^2-1 => k^2=16 => k= -4 or 4.

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