Can isosceles be equilateral

What is an isosceles triangle? How do I prove that these are the vertices of an isosceles triangle: -3,0 , 0,4 , 3,0? Is it possible to have an isosceles scalene triangle? How would you show that a triangle with vertices 13,-2 , 9,-8 , 5,-2 is isosceles?

An isosceles right triangle has legs that are each 4cm. What is the length of the hypotenuse? Triangle XYZ is isosceles. The base angles, angle X and angle Y, are four times the measure of What is the isosceles triangle theorem?

See all questions in Angles with Triangles and Polygons. Theorem There exist isosceles triangles that are not equilateral. Proof A triangle with a base of 10 cm and two other sides each of 20 cm is isosceles , but not equilateral. Are all isosceles triangles equilateral? Zor Shekhtman. Jan 19, Explanation: Theorem There exist isosceles triangles that are not equilateral.

This counter example proves that not all isosceles triangles are equilateral. Related questions How do you classify the triangle given 2 cm, 2 cm, 2 cm? But you have to be careful. Some people notably primary school teachers define isosceles triangles to be those that have exactly two congruent sides. If that is the case, then for them, equilateral triangles are not isosceles.

Show 2 more comments. Active Oldest Votes. The Importance of Definitions Mathematics is a human endeavor. For example, in the question above, we have the definition: Definition: An isosceles triangle is a triangle with at least two congruent sides.

Community Bot 1. Add a comment. Euclid defines isosceles triangles in Definition 20 of Book I of Elements. And I quote, "Of trilateral figures, an equilateral triangle is that which has its three sides equal, an isosceles triangle that which has two of its sides alone equal, and a scalene triangle that which has its three sides unequal. Show 6 more comments.

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