## anonymous one year ago if the point (2/3, y) is on the unit circle, what is y? A.) 2/3 B.) 1/3 C.) √5/3 D.) 4/9

1. anonymous

Do you know what algebraic equation describes the unit circle?

2. anonymous

no i don't

3. welshfella

|dw:1440627793246:dw|

4. anonymous

Ok, the unit circle is described by the equation$x^2 + y^2 = 1$

5. welshfella

its that man Pythagoras again..

6. anonymous

So, if x = 2/3, then we can compute$y^2 = 1 - x^2 \implies y^2 = 1 - \left(\frac{2}{3}\right)^2$

7. anonymous

Yes, Pythagoras, he gets around.

8. anonymous

haha okay I got it now ^_^ thank you guys so much!