a: ΔABC vuông tại A

=>\(AB^2+AC^2=BC^2\)

=>\(BC=\sqrt{6^2+8^2}=10\left(cm\right)\)

Xét ΔABC vuông tại A có AH là đường cao

nên \(AH\cdot BC=AB\cdot AC\)

=>\(AH=\dfrac{6\cdot8}{10}=4,8\left(cm\right)\)

Xét ΔABC vuông tại A có \(sinB=\dfrac{AC}{BC}=\dfrac{8}{10}=\dfrac{4}{5}\)

nên \(\widehat{B}\simeq53^0\)

b: Xét ΔABC vuông tại A có \(cosB=\dfrac{BA}{BC};cosC=\dfrac{AC}{BC}\)

\(AB\cdot cosB+AC\cdot cosC\)

\(=AB\cdot\dfrac{AB}{BC}+AC\cdot\dfrac{AC}{BC}\)

\(=\dfrac{AB^2+AC^2}{BC}=\dfrac{BC^2}{BC}=BC\)

giúp tôi vs cần gấpp

2 A

3 C

4 A

5 D

6 A

7 A

8 B

9 A

10 B

11 A

12 C

13 B

14 D

15 B

16 B

17 A

18 B

19 A

20 A

21 A

1. This is the first time I have made mooncakes for the Mid-Autumn Festival.

2. I had a desire to explore the hidden gems of the city that most tourists miss.

3. Bao wishes he had a big house to get a pet.

1 This is the first time I have made mooncakes for the Mid-Autumn Festival

2 I had a desiration to explore the hidden gems of the city that most tourists miss.

3 Bao wishes he had a big house to get a pet

Topic 2: My Pleasant Experience

One of the most pleasant experiences I’ve ever had was my first camping trip with friends. We went to a beautiful national park last summer. The fresh air, lush greenery, and calming sound of the river made the place unforgettable. We pitched our tents near a lake and spent the day hiking, fishing, and playing games. In the evening, we gathered around a campfire, singing songs and roasting marshmallows. The laughter and bonding made me realize the importance of spending quality time with loved ones. It was a perfect escape from the hustle of daily life, and I felt so refreshed afterward. This trip remains a treasured memory that I’ll always cherish.

1.My full name is Bui Tan Mao. :3
2. My most memorable axperience is going to the beach with my family. >_<

3. I changed my learning level. ^-^

4.My family still keeps the studious stories forever. ;-;
5. I didnt take an eco-tour. :<

1 It has been a few years since I moved to this neighborhood

2 While I was waiting for my food, I noticed a nice painting on the wall

1. It has been few years since I moved to this neighbourhood. 2. While I was waiting my food, I noticed a nice painting on the wall

⇒Cần phải học tập thật tốt,phải có ước mơ và hoạch định ra cho mik một kế hoạch cụ thể,phải rèn đức luyện tài và mỗi người phải có một tình yêu quê hương đất to lớn, cố gắng xây dựng đất nước