Question

The length of two sides of a triangle are $5cm$ and $7cm$. Between what two measures should the length of the third side fall?

Answer 1

It is known that the sum of the two sides of a triangle is greater than the third side, so,

$thirdside<5+7$

$thirdside<12$

And,

$thirdside>7-5$

$thirdside>2$

Therefore, $2<thirdside<12$.

Hence, the third side of the triangle falls between $\left(2,12\right)$.