Is an isosceles triangle considered a regular triangle?

Answer 1

An isosceles triangle is not a regular triangle because it has 1 side that doesn't equal the other 2. For it to be a regular triangle it will need to have all sides the same length.

Here are the three types of triangle classification:

In a equilateral triangle or also known as regular triangle "all" sides must have the same length.

In an isosceles triangle "at least" two sides must have the same length.

In an scalene triangle all sides must be of different lengths

Therefor it can be said that a regular triangle is a type of isosceles triangle since it has at least 2 sides of the same length. But remember if one side changes length and 2 remain the same it becomes an isosceles, if all sides are of different lengths then it becomes scalene.