Isosceles triangles usually have two congruent sides, but the rule is that they actually have at least two. That means that they can also have a third congruent side. That means they are both equilateral and isosceles*, which I personally think is way too confusing, but that's how it works.
Example: A triangle has angles of 60 degrees, 60 degrees, and 60 degrees. It is both isosceles and equilateral.
*I think that equilateral triangles are actually a type of isosceles triangle, so that if you're asked on a math test, for example, whether a triangle is scalene, isosceles, or equilateral, you'd say equilateral.
No, Isosceles is two equal sides, although an equilateral triangle CAN be an isosceles triangle. And Angles of an isosceles triangle are not known (given) - simply two equal sides.
Three, like every other triangle.
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If it doesn't have congruent angles, it's not an isosceles triangle.
The base angles are always congruent.
The Isosceles Triangle Theorem:If two sides of a triangle are congruent, then the angles opposite the sides are congruent.The Converse of Isosceles Triangle Theorem:If two angles of a triangle are congruent, then the sides opposite those angles are congruent.
no because if an scalene triangle had 2 congruent angles it wouldn't be a scalene it would be a isosceles triangle because an isosceles triangle is the only triangle with 2 congruent angles
The isosceles triangle theorem states that if two sides of a triangle are congruent, the angles opposite of them are congruent. The converse of this theorem states that if two angles of a triangle are congruent, the sides that are opposite of them are congruent.