<P> The congruence theorems side - angle - side (SAS) and side - side - side (SSS) also hold on a sphere; in addition, if two spherical triangles have an identical angle - angle - angle (AAA) sequence, they are congruent (unlike for plane triangles). </P> <P> The plane - triangle congruence theorem angle - angle - side (AAS) does not hold for spherical triangles . As in plane geometry, side - side - angle (SSA) does not imply congruence . </P> <P> A symbol commonly used for congruence is an equals symbol with a tilde above it, ≅, corresponding to the Unicode character' approximately equal to' (U + 2245). In the UK, the three - bar equal sign ≡ (U + 2261) is sometimes used . </P>

Is not a criterion for congruency of any two triangles