@ Nguyễn Thị Đương

Bạn ra chỗ " Câu hỏi của tôi " rồi bấm vào đặt câu hỏi nhé, hỏi vô đây dễ bị lạc mất đó ạ.

Bán kính hình tròn là:

`294,33975 : 2 = 147,169875 ( km )`

Đáp số:...

\(\dfrac{2}{5}=\dfrac{4}{10}=0,4\)

Cách ạ:

Ctrl + Shift + Tab. 

\(\dfrac{3}{4}+\dfrac{5}{4}=\dfrac{3+5}{4}=\dfrac{8}{4}=2\)

\(\dfrac{35}{25}+\dfrac{7}{25}=\dfrac{35+7}{25}=\dfrac{42}{25}\)

\(\dfrac{9}{4}+\dfrac{3}{5}=\dfrac{45}{20}+\dfrac{12}{20}=\dfrac{45+12}{20}=\dfrac{57}{20}\)

\(\dfrac{3}{5}+\dfrac{4}{3}=\dfrac{9}{15}+\dfrac{20}{15}=\dfrac{9+20}{15}=\dfrac{29}{15}\)

\(\dfrac{3}{7}+\dfrac{8}{6}=\dfrac{18}{42}+\dfrac{56}{42}=\dfrac{18+56}{42}=\dfrac{74}{42}=\dfrac{37}{21}\)

\(\dfrac{2}{3}+\dfrac{3}{4}=\dfrac{8}{12}+\dfrac{9}{12}=\dfrac{8+9}{12}=\dfrac{17}{12}\)

\(\dfrac{2}{5}+\dfrac{4}{7}=\dfrac{14}{35}+\dfrac{20}{35}=\dfrac{14+20}{35}=\dfrac{34}{35}\)

\(\dfrac{3}{12}+\dfrac{1}{4}=\dfrac{3}{12}+\dfrac{3}{12}=\dfrac{3+3}{12}=\dfrac{6}{12}=\dfrac{1}{2}\)

`#NqHahh`

\(\dfrac{30}{85}=\dfrac{30:5}{85:5}=\dfrac{6}{17}\)

\(\dfrac{49}{77}=\dfrac{49:7}{77:7}=\dfrac{7}{11}\)

Ta có: `5 = 5/1`

`=>` Chọn đáp án B.

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