if the point (2/3,y) on a unit circle what is y?
a) 2/3
b)1/3
c)√5/3
d)4/9

please help!!!!!!

Question

if the point (2/3,y) on a unit circle what is y?
a) 2/3
b)1/3
c)√5/3
d)4/9

please help!!!!!!

anonymous · Answer

please help me i can not get it wrong

kirbykirby · Answer

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kirbykirby · Answer

y is going to be the height of that triangle. ANd you notice you have a right-angled triangle, so you can use the Pythagorean theorem

kirbykirby · Answer

I drew 1 for the hypothenuse since you have a unit circle, and the radius in a unit circle is 1

anonymous · Answer

so$$\frac{ 2 }{ 3 } ^{2}$$ + $$y ^{2}$$ = 1^2

kirbykirby · Answer

um yes, just to be sure write it as $\large \left( \frac{2}{3}\right)^2$
All you have to do then is solve for $y$ :)

anonymous · Answer

so d

kirbykirby · Answer

not quite

kirbykirby · Answer

$$\left( \frac{2}{3}\right)^2+y^2=1^2\
\frac{4}{9}+y^2 = 1\
y^2=1-\frac{4}{9}=\frac{5}{9} $$

kirbykirby · Answer

then square root both sides to find y