Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
5. Parallel Lines and Triangles
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Exercise 38 Page 177

Start by forming the possible triangles.

1

Practice makes perfect

It is given that the angle measures of a triangle are each a multiple of 60. We will find the probability that the triangle is equiangular. Recall that an equiangular triangle is a triangle such that all three interior angles are 60^(∘).

Let's list all of the possible triangles that satisfy the given requirement. Let m∠1, m∠2, and m∠3 be the angle measures of the triangles.

Triangles m∠1 m∠2 m∠3 Sum of the Angles
Triangle I 60 60 60 180

As we can see, there is only one possible triangle and it is equiangular. We can find the probability by dividing the number of favorable outcomes by the number of possible outcomes. Number of favorable outcomes/Number of possible outcomes=1/1=1