Точка M - точка пересечения медиан равностороннего треугольникаABC. Прямая ОМ перпендикулярна плоскости треугольника. Докажите, что плоскость а, которая проходит через медиану CD и прямую ОМ, перпендикулярна прямой AB. Вычислите длину отрезка OD, если AB = 10 см, ОА = 13 см
24см²
Объяснение:
△ABD - равнобедренный т.к. AB = BD по условию,
Пусть BH - высота, она проведена к основанию,
Высота равнобедренного треугольника, проведённая к его основанию является так же и медианой.
⇒ BH - медиана;
AH = HD т.к. H - основание медианы;
AH = AD:2 = 6см:2 = 3см.
△AHB - прямоугольный т.к. ∠AHB = 90°,
Квадрат гипотенузы равен сумме квадратов катетов (т. Пифагора).
AB² = AH²+BH²;
BH² = AB²-AH²;
BH² = 5²-3²;
BH² = 25-9 = 16 = 4²;
BH = 4 см.
Площадь параллелограмма равна произведению его высоты на сторону, к которой она проведена.
BH - высота параллелограмма ABCD, проведённая к стороне AD;
S = BH·AD;
S = 4см·6см = 24см².
Abdilda Tazhibayev was born in 1909 in Akmeshit (now Kyzylorda). Medium
one hundred
The Kipchak tribe Tory clan is descended from Bessary's grandfather. [1] [2] His father, Tazhibai, died in 1915 and was left in the care of his mother, Aimankul. Due to his condition, six-year-old Abdilda was taken to a suburb of Karaozek. Then the future poet lived until the age of thirteen with his mother Aimankul and uncle Daldabay
grows in upbringing. Young Abdilda's poems and literature
His mother and aunt also aroused his curiosity
will be the grandfather. Aimankul is fluent in Arabic and Persian
He was literate, open-minded, and cheerful.
He writes letters to Abdilda and teaches her literature. Abdilda's mother Aimankul, who later became a well-known folk poet and published a collection of poems, at the request of his father Daldabay, recited to the villagers the stories of the East and various Kazakh poems. Passionate, silent, silent
One of his listeners was Abdil. Later, in a small group, Abdilda would recite the stories and epics to his guests and villagers.