Equilateral triangle.
Also a square.
Also a regular pentagon.
Also any regular polygon of any number of sides.
A shape with equal sides and angles is a called a regularshape.
[But there are also other shapes, such as a rhombus, which has equal sides but is not a regular polygon because it does not have equal angles. There is no collective name for such "squashed" polygons".]
Any regular shapes have equal sides, including squares and equilateral triangles. Irregular shapes can also have equal sides, but not equal angles.
The only shape that always has equal sides and equal angles is the square.Other shapes can have equal sides and angles (like a triangle or octagon), but they are not by definition equilateral.--------I think it is worth noting that any regular polygon satisfies the definition. Conversely, as you point out, you have to explicitly specify that it is regular.
It all depends on the shape; different 2D geometrical shapes have different characteristics.Some specialized geometrical shapes:Square: 4 sides; 4 equal sides; 2 pairs of parallel sides; 4 right angles (90 degrees)* A square is a rectangle.Rectangle: 4 sides; 2 pairs of parallel sides; 4 right angles (90 degrees)* A rectangle is not a square.Triangle (equilateral): 3 sides; 3 equal sides; all angles 60 degreesTriangle (isosceles): 3 sides; 2 equal sides (usually the base is the odd one)Triangle (scalene): 3 sides; all uneven sides and anglesRhombus: 4 sides; 4 equal sides; 2 pairs of parallel sides; 4 equal anglesParallelogram: 4 sides; 1 pair of parallel sidesThese are the basic geometrical 2D shapes, but there are others that are more complex.
No, octagons just have to be closed shapes with eight sides - the sides do not have to be of equal length.
The base angles of an isosceles triangle that has two equal sides are equal.
The only similarities between these shapes are that:These shapes have all congruent interior anglesObviously, the shapes are regular and have equal sides.
Squares
Any regular shapes have equal sides, including squares and equilateral triangles. Irregular shapes can also have equal sides, but not equal angles.
Regular shapes are shapes where all the sides and angles are equal. One example of a regular shape is a square because all the sides are the same and all the angles are 90 degrees.
A regular polygon has all sides equal length, and all of the angles are equal.
Squares
An equilateral triangle.
They can have some (or all) equal angles. A rectangle, for example, has all four angles equal but, because its sides are not the same measure, it is not a regular shape.
The shapes that have 3 sides and 3 vertices are called triangles. Triangles are classified based on the lengths of their sides and the measures of their angles. The three most common types of triangles are equilateral triangles (all sides and angles are equal), isosceles triangles (two sides and two angles are equal), and scalene triangles (all sides and angles are different).
It could be a parallelogram, but there are other shapes with more sides.
A square is a regular polygon with 4 equal sides and 4 equal interior angles.
All geometrically regular shapes (i.e. those with sides of equal length) have equal interior angeles.