Did you mean "EQUILATERAL" triangle?  An EQUILATERAL triangle is
one that has all three of its sides the same length, and all
three of its interior angles the same measure.  It's like this:




If you meant "EQUILATERAL" triangle, then all three interior
angles measure 60° each.

But ISOSCELES triangles normally only have TWO sides equal in 
length and only TWO interior angles equal in measure.  They can 
be tall and skinny, like this one:



Notice that 2 of its interior angles are 80°, and the interior angle 
at the top is 20°.  The two interior angles at the bottom are called
"BASE ANGLES" and the interior angle at the top is called the 
VERTEX angle.

ISOSCELES triangles can also be short and fat like this one:

 

Notice that 2 of its interior angles are 33° (the BASE angles), 
and the interior angle at the top (the VERTEX angle) is 114°.

If you add all three interior angles of any triangle you will always
get 180°.  

60°+60°+60° = 180° in the equilateral triangle at the top.
80°+80°+20° = 180° in the tall skinny isosceles triangle.
33°+33°+114°= 180° in the short fat isosceles triangle.

EQUILATERAL triangles are a special kind of ISOSCELES triangle in which
ALL THREE sides and ALL THREE angles are equal.  But an ISOCELES
triangle normally has only TWO sides equal and only TWO angles equal.

Hope this helps you.
Edwin