Exercise 1 Page 646

What do the markers on the sides indicate?

Acute isosceles triangle

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Let's analyze the given triangle.

To classify the triangle by its sides, we need to know how many sides are congruent.

Type	Sides
Scalene	No congruent sides
Isosceles	At least 2 congruent sides
Equilateral	3 congruent sides

Note that there are markers on two sides. They indicate that these sides are congruent. Knowing this, the triangle is isosceles. Now let's look at the angles.

Type	Angles
Acute	3 acute angles
Right	1 right angle
Obtuse	1 obtuse angle
Equiangular	3 congruent angles

We can see that all three angles are acute. This allows us to classify the triangle as an acute triangle. Therefore, the given triangle is an acute isosceles triangle.

Subchapter links

1 Angles of Triangles p.646

2 Congruent Polygons p.646

3 Proving Triangle Congruence by SAS p.647

4 Equilateral and Isosceles Triangles p.647

5 Proving Triangle Congruence by SSS p.648

6 Proving Triangle Congruence by ASA and AAS p.649

7 Using Congruent Triangles p.649

8 Coordinate Proofs p.650

Exercise 1 Page 646

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