Answers:

Given,

The sum of the two sides must be equal to the square of the third side.

The three sides of the triangle – a, b and c.

(i)

a = 9 cm

b = 16 cm

c = 18 cm

????² + ????² = 9² + 16²

=>81 + 256

=>337

????² = 19²

=>361

????² + ????² ≠ ????²

Thus, the given triangle is not right-angled.

(ii)

a =7 cm

b = 24 cm

c = 25 cm

????² + ????² = 7² + 24²

=>49 + 576

=>625

????² = 25²

=>625

????² + ????² = ????²

Thus, the given triangle is a right-angled.