Solution
Step 1:
Write the dimensions of the original rectangle and magnified rectangle.
[tex]\begin{gathered} Dimensions\text{ of original rectangle = 5cm by 7cm} \\ Dimensions\text{ of the magnified rectangle = 5}\times15cm\text{ by 7 }\times\text{ 15cm} \\ =\text{ 75cm by 105cm} \end{gathered}[/tex]
Step 2:
Write the formula of the perimeter of a rectangle
[tex]Perimeter\text{ of a rectangle = 2L + 2B}[/tex]
Step 3:
Find the perimeter of the magnified rectangle.
[tex]\begin{gathered} Perimeter\text{ = 2 }\times\text{ 75 + 2 }\times\text{ 105} \\ =\text{ 150 + 210} \\ =\text{ 360 cm} \end{gathered}[/tex]
Final answer
360cm
