1. **State the problem:** We have a triangle with angles measuring 80°, 58°, and 42°. We need to determine what kind of triangle it is based on its angles. 2. **Recall the types of triangles by angles:** - An **acute triangle** has all angles less than 90°. - A **right triangle** has one angle exactly 90°. - An **obtuse triangle** has one angle greater than 90°. 3. **Analyze the given angles:** - 80° < 90° - 58° < 90° - 42° < 90° 4. Since all three angles are less than 90°, the triangle is an **acute triangle**. **Final answer:** The triangle is an **acute triangle**.