Try It Out -- Chapter 7, Lesson 3: Communicate About Triangles

Iris noticed that in an obtuse triangle the obtuse angle always seems to be much larger than the two acute angles. She wrote a hypothesis that in an obtuse triangle, the sum of the sizes of the two acute angles is always less than the size of the obtuse angle.

Order the steps Iris uses to check her hypothesis.

She concludes that her hypothesis is correct, because obtuse angles are always greater than 90°.
She measures the triangles’ acute angles.
She sums the two acute angles in each triangle. The sum is less than 90° for all six triangles.
She draws six different obtuse triangles.


What is Iris’ first step?


What is her second step?


What is her third step?


What is her final step?

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