Question

If two sides of an isosceles triangle are $3$ cm and $8$ cm, then the length of the third side is __________.

• A. $2$ cm
• B. $8$ cm
• C. $3$ cm
• D. $1$ cm

Answer 1

The correct option is B $8$ cm

Two sides of an isosceles triangle are $3$ 3cm and $8$ cm

In an isosceles triangle two sides are equal.

$1^{st}$ case :

Let the third side be $3$ cm.

For any triangle with sides let say $a,b,c$, then

$a+b>c$ and

$c+b>a$ and

$c+a>b$

In this case $3+3=6<8$

So, the third side of $3$ cm will not possible.

$2^{nd}$ case :

Let third side be $8$ cm

$8+3>8$ and

$8+8>3$

So, $8$ cm is the third side.