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4.2 Isosceles Triangles

Move points B and/or C. What do you notice?

What do you notice about the two base angles of the triangle?

Isosceles triangle conjecture.

If a triangle is isosceles, then the ____________________________________.

Consider the converse of the isosceles triangle conjecture. If the base angles are congruent, then will the triangle always be isosceles? Move point B and C so that the angles are congruent. How do the sides compare?

Converse of Isosceles Triangle Conjecture

If the base angles of a triangle are congruent, then ______________________.

Move points A and B. What do you notice?

Are equilateral triangles also isosceles?

Is every equilateral triangle also equiangular?