2023 AMC 8 Problem 19
Attempt Problem 19 of the 2023 AMC 8 below, then check your answer against the video solution and professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2023 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
19.
An equilateral triangle is placed inside a larger equilateral triangle so that the region between them can be divided into three congruent trapezoids, as shown below. The side length of the inner triangle is the side length of the larger triangle. What is the ratio of the area of one trapezoid to the area of the inner triangle?
Answer: C
Small hint:
Areas of similar triangles scale as the square of side lengths
Big hint:
The inner triangle has of the large triangle’s area
Video solution:
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Written solution:
Since the inner triangle’s side length is the side length of the outer triangle, its area is the area of the outer triangle.
This means that the three trapezoids are the area of the outer triangle.
Therefore, one trapezoid is the area of the outer triangle.
This makes the ratio of the areas of one trapezoid and the inner triangle
Thus, C is the correct answer.
Problem 19 in other years
- 1985 AMC 8
- 1986 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
- 1998 AMC 8
- 1999 AMC 8
- 2000 AMC 8
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