Answer:
y = 0.8425 or y = -0.8425
Step-by-step explanation:
All points in the Cartesian coordinate system have an x and y coordinate, defined by two perpendicular measurements.
If the point is on the unit circle, then the radius of the circle is defined to be 1 unit, and the corresponding right triangle follows the Pythagorean Theorem.
[tex]a^2+b^2=c^2[/tex]
For a unit circle:
[tex]x^2+y^2=1^2[/tex]
Substituting the known value for x, and simplifying...
[tex](-0.5387)^2+y^2=(1)^2[/tex]
[tex]0.29019769+y^2=1[/tex]
Subtracting 0.29019769 from both sides to begin to isolate "y"...
[tex]y^2=1-0.29019769[/tex]
[tex]y^2=0.70980231[/tex]
Applying the square root property...
[tex]\sqrt{y^2}=\pm \sqrt{0.70980231}[/tex]
[tex]y=\pm 0.8424976171...[/tex]
So, (to 4 decimal places), the y coordinate could be either 0.8425 or -0.8425.
With only the given information, either result is a valid answer.
