Lengths of sides of a triangle are 3 cm, 4 cm and 5 cm. The triangle is
(a) Obtuse angled triangle
(b) Acute angled triangle
(c) Right-angled triangle
(d) An Isosceles right triangle
By Pythagoras theorem, \(3^2 + 4^2 = 5^2\). Hence it is a right-angled triangle.