The area of a rectangular field is 124 sq. cm.  The length is 31 cm, then perimeter is?

70 cm 72 cm 75 cm 60 cm

70 cm

Area of the rectangle = l × b ⇒ 124 = 31 × b ⇒ b = 4 cm perimeter = 2 (l + b)                = 2(31 + 4) = 70 cm