Your screenshot is cut off. Without seeing more context, it's hard to say. But usually the little 'o' is often a zero indicating an initial value. It's simply a way to label V in a different way. So you can tell V apart from
The area of a circle is pi times the radius squared. the radius of this circle is 16.8cm, which is 282cm when squared. multiplied by pi it becomes 887cm.
When you rotate across the x-axis it will be in quadrant 4 now and then when rotating a point 180 degrees counterclockwise about the origin our point A(x,y) becomes A'(-x,-y). So all you do is make both x and y negative.
hope this helps:))
