Question

A right-angles triangle has hypotenuse $13$ cm, one side is $12$ cm, then the third side is _________.

• A. $5$ cm
• B. $6$ cm
• C. $7$ cm
• D. $4$ cm

Answer 1

The correct option is A $5$ cm

Given that hypotenuse $h=13$ cm

and one side $b=12$ cm

Let say third side is $P$

Now applying pythagorus theorem:

Therefore, $h^2=b^2+P^2$

$\Rightarrow {13}^2={12}^2+P^2$

$\Rightarrow {13}^2-{12}^2=P^2$

$\Rightarrow P^2=5^2$

Thus third side of a triangle is $5$ cm.