Розрахунок: hRLilg - 1

S =

π

* R^²* α

/ 360

S =

π

* R^²* α

/ 360

$S$ = $\frac{\pi\cdot R^{2}\cdot \alpha}{360}$

S =

R^²* α* π

/ 360

$S$ = $\frac{R^{2}\cdot \alpha\cdot \pi}{360}$

S = 0.00278* R^²* α* π

$S$ = $0.00278\cdot R^{2}\cdot \alpha\cdot \pi$