The volume of a rectangular parallelepiped (V) is equal to the product of the height (H) and the area of the base (S). Thus, in order to find the area of the base, it is necessary to divide the volume by the height, having previously converted dm to cm.
H = 1 dm = 10 cm,
S = V: H = 420: 10 = 42 (cm2).
Answer: the area of the base of the rectangular parallelepiped is 42 cm2.
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