Question

In a right-angled triangle, the length of the longest side is 10 cm and of another side is 8 cm. What will be the length of the third side?

• A. 6 cm
• B. 7 cm
• C. 9 cm
• D. 5 cm

Answer 1

The correct option is A 6 cm

It is given that the triangle is right triangle.

So, the longest side will be the hypotenuse.

We know that in a right triangle, the square of hypotenuse is equal to the sum of the squares of the other two sides.

Let the third side be x metre long.

$\Rightarrow {10}^2=8^2+x^2$

$\Rightarrow x=\sqrt{100-64}$

$\Rightarrow x=6cm$

Therefore, length of the third side is 6 cm.