Question

A triangle whose lengths of sides are $5$ cm, $12$ cm and $13$ cm. The triangle is ____________.

• A. Obtuse-angled triangle
• B. Acute-angled triangle
• C. Right-angled triangle
• D. Triangle is not formed

Answer 1

The correct option is C Right-angled triangle

Given sides of triangle are $5$ cm, $12$ cm, $13$ cm

Now applying pythagorus theorem:

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

$\Rightarrow {13}^2={12}^2+5^2$

$\Rightarrow 169=144+25$

$\Rightarrow 169=169$

These three sides clearly satisfy ptyhagorous theorem.

Therefore, the triangle is RIGHT ANGLED triangle.