The area of a rectangular field is 252  sq. cm.  The length is 21 cm, then perimeter is?

64 cm 68 cm 66 cm 70 cm

66 cm

Area of the rectangle = l × b ⇒ 252 = 21 × b ⇒ b = 12 cm perimeter = 2 (l + b)                = 2(21 + 12 ) = 66 cm