2006 AMC 12A Problem 6

Below is the professionally curated solution for Problem 6 of the 2006 AMC 12A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2006 AMC 12A solutions, or check the answer key.

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Concepts:areasquare (geometry)

Difficulty rating: 1310

6.

The 8×188 \times 18 rectangle ABCDABCD is cut into two congruent hexagons, as shown, in such a way that the two hexagons can be repositioned without overlap to form a square. What is y?y?

66

77

88

99

1010

Solution:

The two hexagons form a square of area 818=144,8 \cdot 18 = 144, so the square has side 12.12.

The staircase cut splits the width into three equal horizontal pieces of length y,y, which together span the full width: y+y+y=18,y + y + y = 18, so y=6.y = 6. (The two vertical steps each rise 128=4,12 - 8 = 4, building the extra height of the square.)

Thus, the correct answer is A.

Problem 6 in Other Years