The perimeter of a rectangular metal plate is 15 cm. Find the length of the rectangular plate (in decimals) whose width is 228 cm. Use estimation in tenths place.

The perimeter of a rectangular metal plate is 15 cm Find the length of the rectangular plate in decimals whose width is 228 cm Use estimation in tenths place class=

Respuesta :

The Solution.

Representing the problem in a diagram, we have

By formula,

[tex]P=2(L+W)[/tex]

In this case,

[tex]P=15\operatorname{cm},L=?,W=\frac{22}{8}cm[/tex]

Substituting these values in the formula above, we get

[tex]15=2(L+\frac{22}{8})[/tex]

Clearing the bracket, we get

[tex]15=2L+(2\times\frac{22}{8})[/tex][tex]\begin{gathered} 15=2L+\frac{11}{2} \\ \\ 15=2L+5.5 \end{gathered}[/tex][tex]\begin{gathered} 15-5.5=2L \\ 9.5=2L \end{gathered}[/tex]

Dividing both sides by 2, we get

[tex]L=\frac{9.5}{2}=4.75\approx4.8\operatorname{cm}[/tex]

Therefore, the correct answer is option C.

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