A sector of a circle as shown in the figure, with angle at the centre equal to 120° has been cut from a circular lamina of radius 21 CM. show that the perimeter of the remaining portion of the lamina is 130 cm .
(solve the sum step by step)​

A sector of a circle as shown in the figure with angle at the centre equal to 120 has been cut from a circular lamina of radius 21 CM show that the perimeter of class=