Passage:
The adjoining figure shows 3 stairs, where L = 85 cm, B = 45 cm and H = 30 cm.
Based on this information choose the correct option for the question.
The perimeter of the bottom is
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 440 cm
The bottom of the stairs is one rectangle. Its length is L, and its width runs under all three stairs: each stair stands one step (B) behind the one below it, and the lowest block reaches back under the other two, so the width is 3B.
Width of the bottom \(=3B=3\times45=135\) cm
Perimeter of the bottom \(=2(L+3B)=2(85+135)=440\) cm