Circle Problems

[oso50]

Hi. I have been struggling with these homework problems for the past hour.I just dont know what to do. Any help is appreciated and thank you.

 

[pka]

The \(m(\widehat{BAC})= \dfrac{\pi}{2}+\dfrac{3\pi}{4}\)
Now you explain why. Hint: \(m(\widehat{AC})=m(\widehat{CB})\) WHY?

 

[skeeter]

arc BAC = 90 degrees + measure of arc AC
can you find the measure of arc AC?

they gave you the area of 3/4 of the circle ...
[MATH]\dfrac{3}{4}\pi r^2 = 461.814[/MATH]can you do the algebra necessary to find the radius?