For any triangle sum of the lengths of two sides is always greater than the length of third side.

The lengths of the sides are 5 cm, 6 cm, 10 cm.

(a) 5 cm + 6 cm > 10 cm.
(b) 6 cm + 10 cm > 5 cm.
(c) 5 cm + 10 cm > 6cm.
Hence, a triangle with these sides is possible.