This is exact for the case of methane, while larger alkanes containing a combination of C–H and C–C bonds generally have bonds that are within several degrees of this idealized value.
ðɪs ɪz ɛɡzˈækt fɚðə kˈeɪs ʌv mˈɛθeɪn, wˌaɪl lˈɑːɹdʒɚɹ ˈælkeɪnz kəntˈeɪnɪŋ ɐ kˌɑːmbᵻnˈeɪʃən ʌv sˈiː ˈeɪtʃ ænd sˈiː sˈiː bˈɑːndz dʒˈɛnɚɹəli hæv bˈɑːndz ðæt ɑːɹ wɪðˌɪn sˈɛvɹəl dᵻɡɹˈiːz ʌv ðɪs aɪdˈiəlaɪzd vˈæljuː.