Giải giúp mình với ạ :)))) Help me

Lỗi nên không vẽ được hình nha bạn !

Bài giải

Kẻ HK \(\perp\)AB tại K ,

Ta có HK//AC ( cùng \(\perp\)AB )  

=> \(\frac{BH}{HC}=\frac{BK}{KA}\)( định lí Ta - lét )

Mà \(\Delta BHK\)vuông cân tại K nên BK = HK => \(\frac{BH}{HC}=\frac{HK}{KA}\left(1\right)\)

Mà \(\Delta AKH\infty\Delta CAM\left(g-g\right)\)

\(\Rightarrow\frac{HK}{KA}=\frac{MA}{AC}=\frac{MA}{AB}=\frac{1}{2}\left(2\right)\)

Từ (1) và ( 2 ) => \(\frac{HB}{HC}=\frac{1}{2}\)

Trả lời:

a) (O′) có OA là đường kính và E(O′) nên OE⊥AC

Tương tự với (O) ta có BC⊥AC nên OE//BC mà OO là trung điểm của AB

⇒E là trung điểm của AC⇒ OE=12BC.

Tương tự OF=12DB mà cung BC bằng cung BD nên BC=BD⇒OE=OF hay cung OE= cung OF.

                                          ~Học tốt!~

đề đau bạn?????

Cho tui xin cái đề thì tui ms giúp đc chứ !!!

gọi số cần tìm là \(\overline{xy}\)

ta có hệ

\(\hept{\begin{cases}5x-y=12\\\left(10y+x\right)-\left(10x+y\right)=36\end{cases}}\)

\(\Rightarrow\hept{\begin{cases}5x-y=12\\-9x+9y=36\end{cases}=>\hept{\begin{cases}45x-9y=108\\-45x+45y=180\end{cases}=>\hept{\begin{cases}36y=288\\5x-y=12\end{cases}=>\hept{\begin{cases}y=8\\5x=20\end{cases}}}}}\)

\(\Rightarrow\hept{\begin{cases}y=8\\x=4\end{cases}}\)

zậy số cần tìm là 48

Whenever you find a new word, try to predict the meaning and look up at the dictionary to know the meaning. 

Chắc vậy :)))))

She wouldn't be very happy because she doesn't have any friends.

Chắc vậy :)))))

she wouldn't very sad because 

1. She said  : " I am working at the restaurant and don't care much for it "

2. Minh spends 2 hours on doing his homework everyday.

3. Because it rained heavily, we were late for school.

4. ( câu này phải là it was chứ vì quá khứ mà )  It was bought last year.

5. You know the man who sat next to me at Nam's birthday party last night.

1."I'm working in a restaurant, and don't care much for it."she said.

- She said that she was working in a restaurant and didn’t care much for it.

2. It takes Minh 2 hours to do his homework every day.

- Minh spends 2 hours doing his homework every day.

3. We were late for school because of the heavy rain.

- Because it rained heavily, we were late for school.

4. People say that they bought this shop last year.

- It is said that they bought this shop last year.

5. Do you know the man who sat next to me at Nam’s birthday party last night?

- You know the man who sat next to me at Nam's birthday party last night, don't you?