Question

If the sum of square of two smaller sides is equal to the square of third side then the triangle will definitely have one of its angles as -

• A. ${60}^o$
• B. ${70}^o$
• C. ${80}^o$
• D. ${90}^o$

Answer 1

The correct option is D ${90}^o$

According to the converse of Pythagoras theorem, " The triangle, which has sum of square of its two sides equal to the square of third side, is a right angled triangle.
Or
A triangle which follow pythagoras theorem is the right angled triangle.

Here, $c^2=a^2+b^2\Rightarrow \angle DEF={90}^o$

Hence, option$\left(d\right)$ correct.