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jmc

prealgebra senior

Problem

In the diagram, there are more than three triangles. If each triangle has the same probability of being selected, what is the probability that a selected triangle has all or part of its interior shaded? Express your answer as a common fraction.

problem
Solution
We can count the total number of triangles that can be chosen directly, by listing them: , , , , and . Of these, the triangles with a part shaded are , , and . So there is probability of selecting a triangle with all or part of its interior shaded.
Final answer
\frac{3}{5}