a) $\overset{\Large\rightharpoonup}{EF}\cdot \overset{\Large\rightharpoonup}{EG}$ b) $\overset{\Large\rightharpoonup}{DA}\cdot \overset{\Large\rightharpoonup}{HG}$ c) $\overset{\Large\rightharpoonup}{AC}\cdot \overset{\Large\rightharpoonup}{HA}$
č)
$\overset{\Large\rightharpoonup}{FH}\cdot
\overset{\Large\rightharpoonup}{HB}$ d)
$\overset{\Large\rightharpoonup}{AG}\cdot
\overset{\Large\rightharpoonup}{BH}$ e)
$\overset{\Large\rightharpoonup}{CG}\cdot
\overset{\Large\rightharpoonup}{FD}$