Question

louise measured the perimeter of her rectangular scrapbook to be 150 cm. if the scrapbook is 42 cm wide, how long is the scrapbook?
a. 75 cm
b. 33 cm
c. 66 cm
d. 31 cm
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Explanation:

Step1: Recall perimeter formula

The perimeter formula for a rectangle is $P = 2(l + w)$, where $P$ is the perimeter, $l$ is the length and $w$ is the width.

Step2: Substitute known values

We know that $P=150$ cm and $w = 42$ cm. So, $150=2(l + 42)$.

Step3: Solve for $l$

First, divide both sides of the equation by 2: $\frac{150}{2}=l + 42$, which simplifies to $75=l + 42$. Then subtract 42 from both sides: $l=75 - 42$.

Step4: Calculate length

$l = 33$ cm.

Answer:

B. 33 cm