Answer:
9
Step-by-step explanation:
Given the width of a rectangle varies inversely with its length, you want to know the width when the length is 8, given the width is 4 when the length is 18.
Inverse relation
When L and W vary inversely, we have ...
W = k/L . . . . for some constant k
Multiplying by L gives ...
W·L = k
Then we have ...
4 · 18 = k = W · 8 . . . . . using the given values
Dividing by 8 gives ...
W = 9 . . . . . . . . . . . . . . . . the width is 9 when length is 8.
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Additional comment
This tells you the area of the rectangle is a constant, 72 square units.
