Câu 3:

2: Xét tứ giác OKEH có 

\(\widehat{OKE}=\widehat{OHE}=\widehat{KOH}=90^0\)

Do đó: OKEH là hình chữ nhật

mà đường chéo OE là tia phân giác của \(\widehat{KOH}\)

nên OKEH là hình vuông

Bạn tách bớt ra nhé!

lỗi r nha bn

lỗi

a: Xét ΔAMC và ΔBMD có 

MA=MB

\(\widehat{AMC}=\widehat{BMD}\)

MC=MD

Do đó: ΔAMC=ΔBMD

Tham khảo

Living in the countryside is really good for your life because of these reasons. First, living in the country can bring you a clean environment. The air is fresher and there are lots of trees, rice fields and rivers, you can walk on the fields or along the rivers to enjoy the clean and fresh air there in the early morning.- Second, living in the countryside is cheaper than in the city because people there have lower income and don’t have the habit of spending a lot of money. If you live in the country, you can save a lot of money. Finally, people in the country are more friendly and opener than people in the city because they live near each other. People live together in a small village so they can talk countryside can have festivals and you can join and fell very happy. In conclusion, there are many benefits of living in the country.

refer

Some people say that they like living in the countryside, the others like living in the city. In my point of view, I prefer living in the countryside for a number of benefits. First of all , It is a quiet and peaceful place. There are a lot of plant species so the air and the food are fresh and clean. We can enjoy a healthy natural condition without worrying much about environmental pollution. We are free to admire the breathtaking landscapes such as huge meadows, peaceful hills or forests. We can also enjoy walking in the forest and picking mushrooms or hunting. Second, There aren't any huge blocks of flats, modern skyscrapers and bothersome traffic jams in the countryside so the air is not polluted. There is no water pollution, either. Moreover, living in the countryside is cheaper than it is in the city, so you can buy many hings at lower prices. The other positive side is the safety. In the rural area the crime rate is much lower. There aren't a lot of housebreaks of burglary and robbery. In the countryside people usually and keep eyes on neighbour's estates. They always react when something strange is happening. Finally, most of the villagers are friendly and hospitable. They are always willing to help each other. Moreover, people in the cities are very susceptible to stress because of pollution, the pressure of work, competitions, etc. In summary, Living in the countryside has many advantages because of fresh air, clean food, specially the people’s friendliness and hospitality.

a) điện trở tương đương của đoạn mạch

R_tđ = R1 + R2 =10 + 20= 30 (Ω)

Cường độ dòng điện chạy qua đoạn mạch

I = \(\dfrac{U}{Rtđ}=\dfrac{6}{30}=0,2\left(A\right)\)

b) vì R1 nối tiếp R2  nên ta có:

I= I1= I2 = I3= 0,2 (A)

-> U1= I1 . R1 = 0,2 .10 = 2 (V)

-> U2 = I2 . R2 = 0,2. 20 = 4 (V)