20 days become a photography expert: Travel Photography Notes(Chinese Edition)

20 days become a photography expert: Travel Photography Notes(Chinese Edition)

Matematika diketahui segitiga ABC dengan panjang sisi-sisinya a = 9 cm b = 7 cm c = 8 cm nilai cos c adalah​

diketahui segitiga ABC dengan panjang sisi-sisinya a = 9 cm b = 7 cm c = 8 cm nilai cos c adalah​

Penjelasan dengan langkah-langkah:

jawaban

C^2=A^2 + B^2 - BC cos C 8^2=9^2 +7^2 - 2x9x 7 cos C

64 81 +49 126 cos C

66126 cos C

cos C=-66 / 126 cos C - 11/21

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