more problems..please tell me if they are correct

[christina18]

1. Find sin A if cos A=8/9 and A is in quadrant IV.
a. -radical (17)/8
b. -radical (17)/9
c. -9/8
d. -radical (17)
*choice B

2. If A is in angle in standard position and satisfies the conditions: the terminal side of A is in quadrant I and lies on the line y=6x, then find the value of sin A.
a. 6radical(37)
b. 6
c. 1/6
d. radical(37)/37
*choice D

3. state in which quadrant the terminal side of the angle -208.7 degrees lies.
a. III
b. IV
c. I
d. II
*choice b

 

[soroban]

Hello, christina18!

1. Find $\displaystyle \sin A$ if $\displaystyle \cos A\,=\,\frac{8}{9}$ and $\displaystyle A$ is in quadrant IV.

$\displaystyle a)\;-\frac{\sqrt{17}}{8}\;\;\;b)\; -\frac{\sqrt{17}}{9}\;\;\;c)\;-\frac{9}{8}\;\;\;d)\; -\sqrt{17}\;\;$ *choice B . . . Right!

2. If $\displaystyle A$ is an angle in standard position and satisfies the conditions:
the terminal side of $\displaystyle A$ is in quadrant I and lies on the line $\displaystyle y\,=\,6x$, then find the value of $\displaystyle \sin A$

$\displaystyle a)\; 6\sqrt{37}\;\;\;b)\;\;6\;\;\;c)\:\frac{1}{6}\;\;\;d)\; \frac{\sqrt{37}}{37}\;$ *choice D . . . Is there a typo?

If answer (d) is: $\displaystyle \,\frac{6\sqrt{37}}{37}$, you are correct.

If answer (a) is: $\displaystyle \frac{6}{\sqrt{37}}$. you are wrong.

3. State in which quadrant the terminal side of the angle $\displaystyle \,-208.7^o$ lies.

$\displaystyle a)\;\;III\;\;\;b)\;IV\;\;\;c)\;I\;\;\;d)\; II\;$ *choice b . . . no

Moving clockwise $\displaystyle 208.7^o$ is equivalent to moving counterclockwise $\displaystyle 151.3^o$
The angle is in quadrant II . . . answer (d)

(Just had a thought . . . Did you pick the second answer, assuming it said "quadrant II"?)

 

[christina18]

Thank you! I see what I did wrong for the 2nd question and the right choice now.