GRAPH COLORING find the chromatic number of these graphs nee

GRAPH COLORING. find the chromatic number of these graphs
need help with h,i,j please

Solution

h) The chromatic number of the graph is 7, since we need 7 colors to color the graph, because the center vertex is connected to the 6 vertices

i) One vertex is connected to 5 vertices in a graph, hence we need atleast 6 vertices to color the graph, therefore the chromatic number of the graph is 6

j) The chromatic number of the graph is 5