Question

lesson 5.4 equilateral and isosceles triangles

1. when an isosceles triangle has exactly two congruent sides, these two sides are the
2. the angle formed by the legs is the
3. the third side of the isosceles triangle is the
4. in an isosceles triangle, the two angles adjacent to the base are called
5. base angles theorem: if two sides of a triangle are congruent, then the angles opposite them are
6. when the sides of a polygon are extended, other angles are formed. the original angles are the
7. the angles that form linear pairs with the interior angles are the
8. name the property: for any triangle △abc, △abc ≅ △abc.
9. name the property: for any triangle △abc, △abc ≅ △abc.
10. name the property: if △abc ≅ △def, then △def ≅ △abc.

Explanation:

1. In an isosceles triangle, the two congruent sides are called legs.
2. The angle formed by the legs is the vertex angle.
3. The third side of an isosceles triangle is the base.
4. The two angles adjacent to the base are base angles.
5. The Base Angles Theorem states that if two sides of a triangle are congruent, then the angles opposite them are congruent.
6. When the sides of a polygon are extended, the original angles are interior angles.
7. The angles that form linear pairs with the interior angles are exterior angles.
8. For any triangle \( \triangle ABC\), \( \triangle ABC\cong\triangle ABC\) is the reflexive property of congruence.
9. (Same as 8)
10. If \( \triangle ABC\cong\triangle DEF\), then \( \triangle DEF\cong\triangle ABC\) is the symmetric property of congruence.

Answer:

1. legs
2. vertex angle
3. base
4. base angles
5. congruent
6. interior angles
7. exterior angles
8. reflexive property of congruence
9. reflexive property of congruence
10. symmetric property of congruence