Do not understand the wording of this circles question...Watch
Apart from that, it looks ok.
I believe the length you have labelled as 2.2 should be 1.8
What did I do wrong? If it's in radians, do I keep the RAD mode on in my calculator even if I'm not dealing with angles? I tried that but I still get the wrong answer http://prntscr.com/vs7ft7
If you add the 4 sectors together you get a (part of) semi circle. Can't see why you'd particularly use radians.
the shaded bits can be joined up to make a semicircle with a small semicircle removed:
grey semicircle area = 𝝅 x 1.82/2
small semicircle area = 𝝅 x 0.52/2
area of shaded bits = 𝝅 x 1.82/2 - 𝝅 x 0.52/2
Area of metal = Area of big circle - area of shaded bits....
once you know the area of metal you can then find its volume.
c2 is the circle around the 4 shaded segments. I can only get the right answer if I leave RAD mode on and do all my calculations with radians, why is that?
See the bears post for simply adding/subtracting 3 circles and semi circles.It's the easiest way.