2008 AMC 10B Problem 7
Attempt Problem 7 of the 2008 AMC 10B 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 2008 AMC 10B solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
7.
An equilateral triangle of side length is completely filled in by non-overlapping equilateral triangles of side length How many small triangles are required?
Answer: C
Small hint:
Area scales with the square of the side length
Big hint:
The big triangle has times the area of a small one
Solution:
The large triangle has side length times that of a small triangle, so its area is times as large.
Since the small triangles tile it without overlap, exactly of them are required.
Thus, the correct answer is C.
Problem 7 in other years
- 2000 AMC 10
- 2001 AMC 10
- 2002 AMC 10A
- 2002 AMC 10B
- 2003 AMC 10A
- 2003 AMC 10B
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- 2004 AMC 10B
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