1986 AMC 8 Problem 13
Attempt Problem 13 of the 1986 AMC 8 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1986 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
13.
The perimeter of the polygon shown is
cannot be determined from the information given
Small hint:
All the angles are right angles, so the horizontal edges and the vertical edges can each be regrouped
Big hint:
The rightward and leftward horizontal edges each span the full width and the upward and downward vertical edges each span the full height
Solution:
Because every angle is a right angle, sliding the edges shows that the horizontal edges together traverse the width twice and the vertical edges traverse the height twice. So the perimeter equals that of the full by rectangle,
The answer does not depend on exactly where the notch is cut.
Thus, the correct answer is C .
Problem 13 in other years
- 1985 AMC 8
- 1987 AMC 8
- 1988 AMC 8
- 1989 AMC 8
- 1990 AMC 8
- 1991 AMC 8
- 1992 AMC 8
- 1993 AMC 8
- 1994 AMC 8
- 1995 AMC 8
- 1996 AMC 8
- 1997 AMC 8
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- 1999 AMC 8
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