Cho tam giác ABC, vẽ tia phân giác của góc B cắt cạnh AC tại D. Vẽ đường thẳng qua A và song song với cạnh BC, cắt tia BD tại O. Chứng tỏ: góc BDC = góc BAD + góc AOD
K
Khách
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LT
8 tháng 10 2020
câu văn trích trong bài cổng trường mở ra
2 từ ghép đẳng lập là cánh cổng, thế giới
l
K
8 tháng 11 2020
1, Would you to go out . No , thanks . I'd to stay ............at........home
2, If you're going to watch the football , you count me .....but.........I don't football
3,I've put ...................2 kg in the last month
4, The japanese eat headthily , she the live .............in.......a long time
5, Sitting too close ...........on........the TV hurls your eyes
6, Becareful .......................what you eat and drink
7. She runs six miles every day to help keep hersely .........................shape
8, Watching TV too mich isn't good ......in............your eyes a long time
TT
19 tháng 11 2020
1, Would you to go out . No , thanks . I'd rather stay .......at.............home
2, If you're going to watch the football , you count me ....out..........I don't football
3,I've put .....on..............2 kg in the last month
4, The japanese eat heathily , so the live ...for.................a long time
5, Sitting too close ....to...............the TV hurls your eyes
6, Becareful ......with.................what you eat and drink
7. She runs six miles every day to help keep herself ....in.....................shape
8, Watching TV too mich isn't good .....for.............your eyes a long time
5 tháng 10 2020
Bài 1 : Gọi số thứ nhất cần tìm là x,số thứ hai cần tìm là y,số thứ ba cần tìm là z. Theo đề bài ta có :
x2 + y2 + z2 = 8125
Mà \(y=\frac{2}{5}x\)=> \(5y=2x\)=> \(\frac{x}{5}=\frac{y}{2}\)(1)
\(y=\frac{3}{4}z\)=> 4y = 3z => \(\frac{y}{3}=\frac{z}{4}\)(2)
Từ (1) và (2) => \(\frac{x}{5}=\frac{y}{2};\frac{y}{3}=\frac{z}{4}\)
+) \(\frac{x}{5}=\frac{y}{2}\Rightarrow\frac{x}{15}=\frac{y}{6}\)
+) \(\frac{y}{3}=\frac{z}{4}\Rightarrow\frac{y}{6}=\frac{z}{8}\)
=> \(\frac{x}{15}=\frac{y}{6}=\frac{z}{8}\)
=> \(\frac{x^2}{15^2}=\frac{y^2}{6^2}=\frac{z^2}{8^2}\)
Áp dụng t/c dãy tỉ số bằng nhau ta có :
\(\frac{x^2}{15^2}=\frac{y^2}{6^2}=\frac{z^2}{8^2}=\frac{x^2+y^2+z^2}{15^2+6^2+8^2}=\frac{8125}{325}=25=5^2\)
=> x2 = 52 . 152 = 752 => x = \(\pm\)75
y2 = 52 . 62 = 302 => y = \(\pm\)30
z2 = 52 . 82 = 402 => z = \(\pm\)40
Bài 2 tự làm
13 tháng 10 2020
Read the following passage and mark the A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks.
Dan and Jenifer were (26) ___ their wedding. Before the big (27) ___,they bought a (28) ___, house with big trees all around and were busy repairing it - (29) ___ the walls and cleaning the floors. There were a little workshop nearby, Jenifer hung her beautiful white (30) ___ there to keep it clean.
Three days ago before the wedding, while Dan and Jenifer were at his family's home, a wild tornado (31) ___ from nowhere. The tornado missed his family's home, but when Dan drove to his house, it was not there. The trees (32) ___ the neighbor's house were gone. The tornado destroyed (33) ___ everything in the neighborhood. Just one thing was (34) ___ standing- the workshop. When Dan looked inside, he discovered the wedding dress untouched. He called Jenifer, “Your dress is here!“ I think your wedding is meant to be.“ The lucky (35) ___ cried at their wedding. “They're grateful to be here,“ explained a friend.
26) A.planned B.to plan. C.plan. D.planning
27) A.festival B.anniversary C.day D.party
28) A.50-year-old B.50-year-olds C.50-old-year D.50-years-old D. fixed
29) A.fixing. B.to fix. C.fix. D.fixed
30) A.skirt B.wedding dress C.dress D.fixed
31) A. blown B.came out C.flew D.left
32) A.as well B.as well as C.from D.but
33) A.almost B.except C.with D.all
34) A.never B.there C.still D.also
35) A.people B.guests C.couple D.invitees