Вопрос:

51. Agar uchburchakning ikki tomoni mos ravishda 8 va 7 cm, ular orasidagi burchak esa 53° bo‘lsa, uchburchakning uchinchi tomonini toping (cm). sin53°=0,8, cos53°=0,6.

Ответ:

Kosinuslar teoremasi: \(c^2=8^2+7^2-2\cdot8\cdot7\cdot\cos53^\circ\).

\(c^2=64+49-112\cdot0.6=45.8\), shuning uchun \(c\approx6.8\) cm.

Javob: 6,8 cm (D).