Question

The perimeter of a triangle is $100$ cm. If two sides are of $35$ cm and $30$ cm, find the third side of the triangle.

Answer 1

Finding the third side of the triangle :

The perimeter is the total measure of the boundary of the figure, it is given to be $100$cm.

Given that, the length of two sides are $35$cm and $30$cm.

$$\begin{gathered} \mathrm{Perimeter}=\mathrm{Sum}\mathrm{of}\mathrm{all}\mathrm{sides} \\ 100\mathrm{cm}=35\mathrm{cm}+30\mathrm{cm}+\mathrm{Third}\mathrm{side} \\ 100\mathrm{cm}=65\mathrm{cm}+\mathrm{Third}\mathrm{side} \\ 100\mathrm{cm}-65\mathrm{cm}=\mathrm{Third}\mathrm{side} \\ 35\mathrm{cm}=\mathrm{Third}\mathrm{side} \end{gathered}$$

Therefore, the length of the third side is $35$ cm.