Calculations at an annulus (circular ring). A semi-annulus is a half annulus. This shape is as well an annulus sector and an annulus segment. Only when an annulus is halved, these two are identical.
Enter at radiuses and breadth two values and choose the number of decimal places. Then click Calculate.
Formulas:
pi:
Radius, breadth and perimeter have the same unit (e.g. meter), the area has this unit squared (e.g. square meter).
A semi-annulus is a geometrically simple figure consisting of two semicircular arcs of different sizes and two straight lines of equal length, the length of which is determined by the difference between the radii of the two semicircles. Its area is equal to the area of the larger semicircle minus that of the smaller one, or half the area of the corresponding annulus. Its perimeter consists of the perimeter of the larger semicircle, minus the straight edge of the smaller semicircle, plus the arc length of the smaller semicircle. In relation to the annulus, the perimeter is half of the annulus's total perimeter (the outer and inner circles combined) plus twice the breadth of the annulus. The longest interval of the annulus can be found in exactly the same way in the semi-annulus.
The semi-annulus is axially symmetric with respect to one axis of symmetry. This axis runs perpendicular to the bisecting line of the annulus, passing through its center point.
In the real world, semi-annuli are encountered in various contexts, among other things as structural components. Bridge arches and tunnel tubes, for instance, may have this form, with the flat edge of course at the base. Additionally, pipe clamps are often constructed from two equal semi-annuli. In such cases, the semi-annulus represents the shape of the two-dimensional cross-section. When extended into the third dimension, the simplest resulting form is a generalized cylinder based on this cross-section. Its volume is calculated by multiplying the area of the semi-annulus by the height of the cylinder.