Some equilateral triangles are not isosceles? true or false

False

Step-by-step explanation:

Definition of equilateral triangle :- A triangle having all sides equal is known as equilateral triangle.

Definition of isosceles triangle :- A triangle having any two sides equal is known as isosceles triangle.

By the above definition is is clear that if a triangle is equilateral triangle then it will satisfy the definition of isosceles triangle too.

Therefore, the statement "some equilateral triangles are not isosceles" is false.

the answer to this is a. a^2 + b^2 = c^2