Một mảnh đất hình bình hành có tỉ số giữa chiều cao và đáy là 4/7, chiều cao kém đáy 18m. Tính diện tích mảnh đất đó. Vẽ sơ đồ biểu thị chiều cao và đáy nữa ạ

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Đáp án:

 hiệu số phần bằng nhau là :
   `7 - 4 = 3` ( phần )
chiều cao mảnh đất là :
  `( 18 : 3 )` x `4 = 24 ( m )`
độ dài đáy mảnh đất là :
 `( 18 : 3 )` x `7 = 42 ( m )`
diện tích mảnh đất đó là :
 `42` x `24 = 1008 ( m² )`
     đáp số : `1008m²`

Giải thích các bước giải:

 

Tỉ số giữa chiều cao và đáy là $\dfrac{4}{7}$ 

⇔ chiều cao chiếm 4 phần còn độ dài đáy chiếm 7 phần

Hiệu số phần bằng nhu là:

${7}$ ${-}$ ${4}$=${3}$ (phần)

Chiều cao hình bình hành là:

${18}$:${3}$×${4}$=${24}$ ${(m)}$

Độ dài đấy hình bình hành là:

${24}$+${18}$=${42}$ ${(m)}$

Diện tích hình bình hành là:

${24}$×${42}$=${1008}$ ${m^2}$

Đ/số: ${1008}$ ${m^2}$

 

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