Question

A point is in Quadrant-III and on the Unit Circle. If its x-coordinate is -4 / 5, what is the y-coordinate of the point?​

Answer 1

Answer:

-4/5

Step-by-step explanation:

because in 3rd quadrant, y-axis coordinates are also -ve

Answer 2

Answer:

y coordinate = sin(x) = ±$\frac{\frac{3}{5} }{1}$ =  ±$\frac{3}{5}$

Step-by-step explanation:

In a unit circle

X coordinate = cos(x)

y coordinate = sin(x)

If cos(x) = $-\frac{4}{5}$

the hypotenuse is 1 and the adjacent leg is  $-\frac{4}{5}$.

then the other leg is ±$\sqrt{1^{2}-(\frac{4}{5} )^{2} }$ = ±$\sqrt{1-\frac{16}{25} }$ = ±$\sqrt{\frac{9}{25} }$ = ±$\frac{3}{5}$

The opposite leg is  ±$\frac{3}{5}$

y coordinate = sin(x) = ±$\frac{\frac{3}{5} }{1}$ =  ±$\frac{3}{5}$

Since it is in the third quadrant, both x and y are negative.

then sin(x) is negative or -$\frac{3}{5}$