the diagonal of a rectangle is cm and its area is 20 sq . cm . the perimeter of the rectangle must be :
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
multiply(const_2, sqrt(add(add(20, 20), add(add(20, 20), const_1))))