Xét △ABC có MN//BC(giả thiết) ta có:

AM/AB=AN/AC

Mà AM=8cm

AB=20cm

AC=15cm

⇒8/20=AN/15

⇒AN=6(cm)

Mà AC=15cm

➞NC=15-6=9(cm)

​

Xét △ABC có AB=12cm, AM=4cm:

⇒MB=8cm

Xét △ABC có MN // BC(giả thiết), ta có:

MB/AB=NC/AC(ĐỊnh lý Ta-let)

Mà MB=8cm, AB=12m, NC=10cm

⇒8/12=10/A

⇒AC=15cm

(Mình không biết nó có đúng k! Nếu bạn cảm thấy sai thì chỉ giúp mình chỗ sai nhé!♫)

Cho △ABC có 3 cạnh AB, BC, CA lần lượt là 6, 8,10. Lấy E và F thuộc AB và AC sao cho AE=2, AF=4.Gọi giao của CE,BF là H. Tính tỷ số EH và CH .

❤Read the text about and decide if the statements are true(T) or false(F)

The dragon dance and the lion dance originated from China, and it has been introduced to many parts of the world. The dragon dance and lion dance are also popular in some traditional festivals in Vietnam. Dragons symbolize wisdom, power and wealth, and they are believed to bring good luck to people. The origin of the dragon dance can be dated back to the Han Dynasty(206 BC-220 AD). It was used in a ceremony for worshiping ancestors and praying for rain, and it gradually developed into an entertainment activity. By the Tang Dynasty (618-907) and the Song Dynasty(1960-1279), it had become a common ceremonial activity in festivals like CHinese New Year.

The dragon body is woven in a round shape of thin bamboo strips, segment-by-segment, and covered with a huge red cloth with dragon scalees decorating it. The whole dragon is usually up to the 30 meters in length - and people hold rods every 1 to 2 meters to raise the dragon segments.

☘1.The dragon dance came from China.

2.People think that the dragon dance is associated with luck.

3.The dragon dance was firstly performent for entertainment.

4.People performed the dragon dance to pray for less rain.

5.The whole dragon is usually much more than 30 meters in high.

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Vì sao có hiện tượng mỏi cơ?

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➸Write an email to Emma. In your email, you should:

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