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Answer:
-3 in
Explanation:
There are several ways you can go at this.
1. Find the "unit rate" of descent:
inches/seconds = (-4.5 in)/(1.5 s) = -3 in/s
In one second, the spider is -3 in from the surface.
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2. Use a proportion:
inches/seconds = (-4 1/2)/(1 1/2) = x/1
Multiply by 1 and simplify.
(-9/2)/(3/2) = x = -9/3 = -3
In one second the spider is -3 in from the surface.
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3. Recognize that 1 is 2/3 of 1 1/2. Then the spider will be 2/3 of -4 1/2 inches from the surface:
(2/3)(-4 1/2) = (2/3)(-9/2) = -9/3 = -3 . . . inches
This is equivalent to writing the proportion of #2 as ...
(inches in 1 s)/(inches in 1.5 s) = (1 second)/(1.5 seconds)
x / -4.5 = 1/1.5
x = -4.5(2/3) = -3