how to find length of a side of a triangle if two are given???????

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Please find below the solution to the asked query:

$$\begin{gathered} \mathrm{In} \mathrm{such} \mathrm{question}, \mathrm{perimeter} \mathrm{should} \mathrm{also} \mathrm{be} \mathrm{given}.\mathrm{Without} \mathrm{perimeter}, \mathrm{we} \mathrm{cannot} \\ \mathrm{find} \mathrm{the} \mathrm{third} \mathrm{side}. \\ \mathrm{Perimeter}=\mathrm{Sum} \mathrm{of} \mathrm{all} \mathrm{sides} \\ \mathrm{e}.\mathrm{g}. \mathrm{In} ∆\mathrm{ABC} \\ \Rightarrow \mathrm{Perimeter}=\mathrm{AB}+\mathrm{BC}+\mathrm{CA} \\ \Rightarrow \mathrm{CA}=\mathrm{Perimeter}-\left(\mathrm{AB}+\mathrm{BC}\right) \\ \mathrm{Hence} \mathrm{in} \mathrm{a} \mathrm{question} \mathrm{if} \mathrm{perimeter} , \mathrm{AB} \mathrm{and} \mathrm{BC} \mathrm{are} \mathrm{given} \mathrm{then}, \mathrm{we} \mathrm{can} \mathrm{find} \mathrm{CA} \end{gathered}$$

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