Question

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

Answer 1

Do you know what algebraic equation describes the unit circle?

Answer 2

no i don't

Answer 3

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

Answer 4

its that man Pythagoras again..

Answer 5

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

Answer 6

Yes, Pythagoras, he gets around.

Answer 7

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