a point lies on the unit circle whose x-coordinate is 1/4. if the point lines in the fourth quadrant then which of the following is its y-coordinate. A.)

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a point lies on the unit circle whose x-coordinate is 1/4. if the point lines in the fourth quadrant then which of the following is its y-coordinate. A.) 3/4 B.)\(-\sqrt{}15/4\)

Guest Apr 14, 2016

CPhill · Answer 1 · 2016-04-14T11:13:20

Since x^2 + y^2 = 1 then

(1/4)^2 + y^2 = 1

1/16 + y^2 = 1

y^2 = 1 - 1/16

y^2 = 15/16 ..... take pos/neg square roots........

y = ± √(15/16 = ± √(15)/4

But....y is negative in this quadrant, so the answer is : - √(15)/4