What are the bond angles of propane? In an organic chemistry book, I find out that the observed C-C-C bond angle is approximately $111.66^\circ$. What about the C-C-H and H-C-H bonds shown in the picture below?
According to “Structure of Free Molecules in the Gas Phase”, in CRC Handbook of Chemistry and Physics, 97th Edition (2016), William M. Haynes, ed., CRC Press/Taylor and Francis, Boca Raton, FL., the bond angles in propane are

$\angle\ce{CCC}=112^\circ$ 

and

$\angle\ce{HCH}=107^\circ$ 

Therefore, the remaining bond angles should each be about

$\angle\ce{CCH}\approx109^\circ$