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Students were asked to write a formula for the length of a rectangle by using the formulafor its perimeter, p= 2l+ 2w. Three of their responses are shown below.I. L=1/2p-wII. L= 1/2 (p-2w)III. L=(p-2w)/2 Which responses are correct?1) I and II, only3) I and III, only2) II and III, only4)I, II, and III

User Tgoossens
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1 Answer

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Given the formula for the perimeter of a rectangle:


p=2l+2w

Where "p" is the perimeter, "l" is the length, and "w" is the width.

You can write a formula for the length of the rectangle by solving the given formula for "l":

1. Apply the Subtraction Property of Equality by subtracting this term from both sides of the equation:


2w

Then:


p-(2w)=2l+2w-(2w)


p-2w=2l

2. Apply the Division Property of Equality by dividing both sides of the equation by 2:


(p-2w)/(2)=(2l)/(2)
l=(p-2w)/(2)

3. You can rewrite the equation in this form:


l=(1)/(2)(p-2w)

Or you can rewrite it in the following form:

- Separate each numerator with the same denominator:


(p)/(2)-(2w)/(2)=l

- Simplify:


l=(1)/(2)p-w

Hence, the answer is: Option 4.

User DJanssens
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