The measure of each angle of a triangle is a multiple of 30°. What is the probability that the triangle has at least two congruent angles?

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(1) Answers

Skyheart

Well, the triangle could have a few possibilities to get the angles. They are:
30-30-120
30-60-90
30-90-60
30-120-30
60-30-90
60-60-60
60-90-30
90-30-60
90-60-30
Thus, there are 9 possible cases. Out of them 3 are good, so the probability is 1/3, or 33%.