Question

Classify the triangle by its sides and angles if it has angle measures of 47°, 12°, and 121°. Check all that apply .

Answer 1

2 Answers:

• Obtuse
• Scalene

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Step-by-step explanation:

The 121° angle is larger than 90°, so that's what makes the triangle obtuse. For any obtuse triangle, only one angle can be larger than 90°. The other two angles are less than 90°

If a triangle is obtuse, then it cannot be acute. Recall that acute triangles have all angles less than 90°.

Also obtuse triangles cannot be right triangles because we need one angle to be exactly 90°.

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The three angles 47°, 12°, and 121° are all different values. This leads to all three sides being different lengths. Therefore, the triangle is scalene.

The triangle cannot be isosceles because we would need exactly two sides to be the same length.

Similarly, the triangle cannot be equilateral because we need all 3 sides to be the same length (and all three angles need to be 60° each).