A polygon has 4 sides and length of the sides are 4 cm, 4 cm, 4 cm and 5 cm. This polygon is regular.
In regular polygon all sides and angles are equal. In the given polygon all the sides are not equal. So, this is not a regular polygon.
A polygon has 4 sides. Lengths of the sides are 4cm,4cm,4cm and 5cm. This is a regular polygon.
The triangle whose lengths of sides are 4 cm, 5 cm and 6 cm is a right-angled triangle.