The area of a triangle is equal to the area of a rectangle with a length of 9 cm and a width of 4 cm. It is known that its height is 6 cm. What is its base in cm? (Solution of column equation)
一个三角形的面积与长9厘米、宽4厘米的长方形面积相等，已知它的高是6厘米，请问它的底是多少厘米？(列方程解)
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