Question

Determine whether the triangle whose lengths of sides are 3 cm, 4 cm, and 5 cm is a right angled triangle?

Answer 1

The given lengths of the sides are $3\text{cm},4\text{cm}$ and $5\text{cm}$

$3^2=3\times 3=9;$

$4^2=4\times 4=16;$

$5^2=5\times 5=25$

We know that

$9+16=25$

$3^2+4^2=5^2$

Therefore, the triangle is a right-angled triangle.

Note : In any right-angled, triangle the hypotenuse happens to be the longest side.

In this example the side with length 5 cm is the hypotenuse.