A circumference
A circumference
It is called a radius
A region of a circle called a pie slice is also called a sector. The sector is one of the main slices of a circle, the other is called a segment.
It's called a "chord" of the circle. If it happens to go through the center of the circle,then it's also called a "diameter" of the circle, and no other chord in the same circlecan be longer.
Assuming that primeter is your way of spelling perimeterand rectangel is your way of spelling rectangle, the answer is 22 metres.
It may be called a 90 degree section , or 1 fourths of a circle.
Is also called a segment.
half of the radius the radius is half of the diameter the diameter is the with of the circle. This also can be called a quadrent circle.
a hemisphere
If you're asking for the PRIINISTER its Rhodri Morgan
semicircleA half circle is called a semicircle.Half a circle is a semi-circle
That's a 'chord' of the circle.If it passes through the center of the circle, then it's also called a 'diameter'of the circle, and no other chord of that circle can be longer than it is.