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CEMC Gauss (Grade 8), 2007

Number theory Difficulty 3.0 AMC 10/12 Find the answer Canada

A lattice point is a point $(x, y)$ , with $x$ and $y$ both integers. For example, $(2, 3)$ is a lattice point but $(4, \frac{1}{3})$ is not. In the diagram, how many lattice points lie on the perimeter of the triangle?

(A) $16$ (B) $18$ (C) $20$ (D) $23$ (E) $30$

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