Theo hình, ta có: \(DI=\frac13\times DC\)

mà DC=AB(ABCD là hình chữ nhật)

nên \(\frac{DI}{AB}=\frac13\)

Vì DI//AB

nên \(\frac{OD}{OB}=\frac{OI}{OA}=\frac{DI}{AB}=\frac13\)

=>\(\frac{DO}{DB}=\frac14\)

=>\(S_{DOI}=\frac14\times S_{DBI}\)

=>\(S_{DBI}=4\times S_{DOI}=4\times160=640\left(\operatorname{cm}^2\right)\)

Ta có: \(DI=\frac13\times DC\)

=>DC=3DI

=>\(\)\(S_{DBC}=3\times S_{DBI}=3\times640=1920\left(\operatorname{cm}^2\right)\)

ABCD là hình chữ nhật

=>\(S_{ABCD}=2\times S_{DBC}=2\times1920=3840\left(\operatorname{cm}^2\right)\)

2 Is your family with you hear

3 Does your wife enjoy athletics

4 Do you like life here in Italy?

5 Are you worried about the Italian Champion, Giacomo Zanetti

6 Dp you have any advice for young athletes

Cảm ơn c nhiều nha!!!!

Tổng là : 36 x 2 = 72 

 Số kia là : 72 - 50 = 22

~ HT ~

4: Ta có: x+2x+...+18x=1368

\(\Leftrightarrow153x=1368\)

hay \(x=\dfrac{152}{17}\)

2KMnO₄ → K₂MnO₄ + MnO₂ + O₂

Cảm ơn bạn nhiều 🥰🥰🥰

Part 3

I

1 T

2 F

II

3 My family can receive much happiness from doing volunteer

4 My family raises some fund for them, and also cook meal for them

Part IV

I

1 Although I was tired last night, I stayed up late to watch a game show

2 Ha noi is smaller than HCM City

II

1 Sleep more, but try to wake up at the usual time

2 Be careful with what you eat and drink

III

1 - B

2 - D

3 - A

4 - E

5 - F

B

6 so

7 or

8 because

9 and

10 more