The equations
[tex]x = r*\cos(\theta)\\\\y = r*\sin(\theta)[/tex]
are useful to convert from polar to Cartesian
So,
[tex]x = r*\cos(\theta)\\\\x = r*\cos\left(\frac{\pi}{3}\right)\\\\x = r*\frac{1}{2} \ \text{ use unit circle} \\\\x = \frac{1}{2}r[/tex]
Answer: Choice A
