Question

The sides of a triangle are 6cm, 7cm and 8 cm. Is this triangle a right-angled triangle?

• A. Yes
• B. No

Answer 1

The correct option is B No

The given triangle will be a right-angled triangle if square of hypotenuse(largest side) = sum of squares of othere two sides (pythagoras theorem holds true).
i.e.,$8^2=6^2+7^2$
$\because 8^2=8\times 8=64\text{and}{6}^2+7^2=(6\times 6)+(7\times 7)=36+49=85$
$\because 64\ne 85\Rightarrow 8^2\ne 6^2+7^2$
$\therefore$ The given triangle is not a right-angled triangle