Circumference - increase

If we increase the length of the side of the square by one-third, the circumference of the square will increase by 18 cm. Calculate the length of the side of the square.

Final Answer:

a =  13.5 cm

Step-by-step explanation:

$$\begin{gathered} o=4a \\ 4(a+\frac{a}{3})=4a+18 \\ 4\cdot (a+a/3)=4\cdot a+18 \\ 4a=54 \\ a=\frac{54}{4}=13.5 \\ a=\frac{27}{2}=13.5=\frac{27}{2}\text{cm}=13.5\text{cm} \end{gathered}$$

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