Answer:
D. obtuse
Explanation:
The largest angle tells you the sort of triangle it is. Here, the largest angle is more than 90°, so the triangle is classified as obtuse.
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If it were exactly 90°, the triangle would be a right triangle. A largest angle less than 90° means the triangle is an acute triangle.
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Additional comment
The two angles opposite the obtuse angle have the same measure. That means the triangle can be further classified as isosceles. In an equilateral triangle, all three angles have the same measure: 60°.