(i) We know that in a right angled triangle, the square of the largest side is equal to the sum of the squares of the smaller sides.
Here, the larger side is c, which is 25 cm.
c2=625
Given that,
a2+b2=72+242
=49+576=625=c2
Thus, the given triangle is a right triangle.
(ii) We know that in a right angled triangle, the square of the largest side is equal to the sum of the squares of the smaller sides.
Here, the larger side is c, which is 18 cm.
c2=324
Given that
a2+b2=92+162
=81+256
= 337 which is not equal to c2
Thus, the given triangle is not a right triangle.