The diagonal of a rectangle is cm and its area is 20 sq. cm. The perimeter of the rectangle must be:  Choose the correct choice from the following answers:
A) 18	B) 77	C) 625	D) 276	E) 191

Rationale: explanation : ( or ) { \ color { black } l ^ { 2 } + b ^ { 2 } = 41 } also , { \ color { black } ( l + b ) ^ { 2 } = l ^ { 2 } + b ^ { 2 } + 2 lb } = 41 + 40 = 81 ( l + b ) = 9 . perimeter = 2 ( l + b ) = 18 cm . answer : a ) 18
Answer: A