Areas: Surface Areas, Centroid Coordinates

Here you will find formulas for determining the surface areas and centroid coordinates of simple shapes. This information will assist you, for example, in determining the centroid of composite areas composed of simple subregions or in calculating area moments of inertia.

Areas: Surface Areas, Centroid Coordinates.

Table 1: Surface areas and centroid coordinates of shapes
Areas
Circle areas	Circle		$$\begin{align}A&=r^2 \cdot \pi\\A&=\dfrac{d^2 \cdot \pi}{4}\\C&=2\cdot r \cdot \pi = d \cdot \pi\end{align}$$	$$\begin{align}O_x &= r\\O_y &= r\end{align}$$

$O:$	Centroid
$r:$	Radius
$d:$	Diameter
$O_x:$	Centroid coordinate
$O_y:$	Centroid coordinate
$A:$	Area
$C:$	Circumference

\(O:\)	Centroid
\(r:\)	Radius
\(d:\)	Diameter
\(O_x:\)	Centroid coordinate
\(O_y:\)	Centroid coordinate
\(A:\)	Area
\(C:\)	Circumference