Problem 5 · 2010 Math Kangaroo
Easy
Geometry & Measurement
perimeter
The perimeter of the figure pictured on the right is …
Show answer
Answer: E — 6a+8b
Show hints
Hint 1 of 2
The little steps shift left and right, but the total across and total down are easy to add.
Still stuck? Show hint 2 →
Hint 2 of 2
A staircase has the same perimeter as its bounding rectangle.
Show solution
Approach: add all sides (staircase = bounding rectangle)
- The horizontal pieces are a, a, a on the steps plus the long bottom of length a+a+a = 3a, totalling 6a.
- The vertical pieces are b, 2b, b on the steps plus the tall left side of length b+2b+b = 4b, totalling 8b.
- Perimeter = 6a + 8b.
Mark:
· log in to save