Sắt đoàn
45
9
Vẽ và tia phân giác Ot. Lấy điểm A thuộc Ox và điểm B thuộc Oy sao cho OA = OB. C là điểm bất kì trên Ot.
a, Chứng minh .
b, OC cắt AB ở D. tính góc ADO
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và tia phân giác Ot. Lấy điểm A thuộc Ox và điểm B thuộc Oy sao cho OA = OB. C là điểm bất kì trên Ot.format('truetype')%3Bfont-weight%3Anormal%3Bfont-style%3Anormal%3B%7D%3C%2Fstyle%3E%3C%2Fdefs%3E%3Ctext%20font-family%3D%22math1ed582716bfb4738ccd92405301%22%20font-size%3D%2216%22%20text-anchor%3D%22middle%22%20x%3D%227.5%22%20y%3D%2216%22%3E%26%23x2206%3B%3C%2Ftext%3E%3Ctext%20font-family%3D%22Arial%22%20font-size%3D%2216%22%20text-anchor%3D%22middle%22%20x%3D%2231.5%22%20y%3D%2216%22%3ECAB%3C%2Ftext%3E%3Ctext%20font-family%3D%22Arial%22%20font-size%3D%2216%22%20text-anchor%3D%22middle%22%20x%3D%2265.5%22%20y%3D%2216%22%3Ec%26%23xE2%3Bn%3C%2Ftext%3E%3C%2Fsvg%3E)
.
