$4.$ For the graph shown in Figure $3,$ take the edge $($e$,$ f$)$ on the outer face as

$($v$1,$ v$2)$ and the vertex h as vn$.$

$($a$)$ What would be the coordinates of each vertex in a straight$-$line grid

drawing according to the algorithm by De Fraysseix, Pach, Pollack? $8$

$($b$)$ Draw the graph on a grid paper.