If area of a square is 100 m² and a rectangle is drawn along its side as shown in the figure such that area of complete figure is 380 m², then find the perimeter of the rectangle outside the square.

76 m

Area of square ABCD = (side)²

                          100  = (side)²

                          side = 10 cm

Area of rectangle BEFC = Area of rectangle - area of square

⇒ BC × BE =  380 - 100

⇒ 10 × BE =  280                               [BC is side of square, i.e. 10 m]

⇒ BE =  28 m

Now,

Perimeter of rectangle BEFC = 2(BC + BE)

                                             = 2(10 + 28)

                                             = 76 m