2003 AMC 10A Problem 23


A large equilateral triangle is constructed by using toothpicks to create rows of small equilateral triangles. For example, in the figure we have 33 rows of small congruent equilateral triangles, with 55 small triangles in the base row. How many toothpicks would be needed to construct a large equilateral triangle if the base row of the triangle consists of 20032003 small equilateral triangles?


(A) 1,004,004(B) 1,005,006(C) 1,507,509(D) 3,015,018(E) 6,021,018\mathrm{(A) \ } 1,004,004 \qquad \mathrm{(B) \ } 1,005,006 \qquad \mathrm{(C) \ } 1,507,509 \qquad \mathrm{(D) \ } 3,015,018 \qquad \mathrm{(E) \ } 6,021,018

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Problem Tags: Counting and probability Geometry

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Category: AMC 10A
Points: 4
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