Question

perimeter = 18
3+3
length of missing side l =
(rectangle with width 3 and length l)

Explanation:

Step1: Recall perimeter formula for rectangle

The perimeter \( P \) of a rectangle is given by \( P = 2\times (length + width) \). Here, the width is 3, and the perimeter is 18. Let the length be \( L \). So, \( 18 = 2\times (L + 3) \).

Step2: Solve for \( L \)

First, divide both sides of the equation by 2: \( \frac{18}{2}=L + 3 \), which simplifies to \( 9 = L + 3 \). Then, subtract 3 from both sides: \( L=9 - 3 \).

Step3: Calculate the value of \( L \)

\( L = 6 \).

Alternatively, using the sum of all sides: A rectangle has two lengths and two widths. Let the length be \( L \), width be 3. So perimeter \( = L + L + 3 + 3 = 2L + 6 \). Set equal to 18: \( 2L + 6 = 18 \). Subtract 6: \( 2L = 18 - 6 = 12 \). Divide by 2: \( L=\frac{12}{2}=6 \).

Answer:

6