\[
e” = \frac{AREA}{R^2 \sin 01″}
\]
Where:

$e”$ = spherical excess

$AREA$ = area of triangle

$R$ = average radius of curvature

\[ C_2 = \frac{E_1}{3} \] Where:

$C_2$ = 2nd correction

$E_1$ = Error in 1st correction

$e”$ = spherical excess

$AREA$ = area of triangle

$R$ = average radius of curvature

If the triangle does not close to 180°, proceed to 2nd correction2nd correction:

\[ C_2 = \frac{E_1}{3} \] Where:

$C_2$ = 2nd correction

$E_1$ = Error in 1st correction

Add the 2nd correction algebraically