質問: "the total area of a square and rectangle is 496 sq cm. the s" "the total area of a square and rectangle is 496 sq cm. the side of the square is 14 cm. what is the sum of the perimeter of square and rectangle, if the length of the rectangle is 25 cm?"
回答: "a2 + lb = 496 ⇒ 142 + 25b = 496 ⇒ 196 + 25b = 496 ⇒ 25b = 496 – 196 ⇒ 25b = 300 ⇒ b = 12 cm perimeter of square = 4a = 4 × 14 = 56 cm perimeter of rectangle = 2 × (l + b) = 2 × (25 + 12) 2 × 37 = 74 cm required sum = 56 + 74 = 130 cm"