4. Let n 2 3, and let Ĉ„ be the "pyramid graph" with n+1 vertices obtained from the cycle graph Cn by adding one new vertex labelled 0 that is connected to each old vertex of C, by one edge. For...

Extracted text: 4. Let n 2 3, and let Ĉ„ be the "pyramid graph" with n+1 vertices obtained from the cycle graph Cn by adding one new vertex labelled 0 that is connected to each old vertex of C, by one edge. For example, for n = 3 we have: C3 And for n = 4 we have: C4 ĈA (a) Find the chromatic number of Ĉn. (You may use without proof the fact that the chromatic number of C, is 2 for n even, and 3 for 3