<u>SAS Criterion:</u> If two sides and the included angle of one triangle are equal to the corresponding sides and angle of another triangle, the triangles are congruent.
From the diagram you can see that:
<A ≅ <F ≅ <P
AB ≅ GF ≅ PQ
AC ≅ FE ≅ PR
This means that ΔABC, ΔFGE, and ΔPQR are congruent.
An optical double is an illusion—the stars are at vast distances from each other and are not actually orbiting each other—whereas in a visual binary, the stars are actually orbiting each other. its total energy output into all space
