Question

What universal set(s) would you propose for each of the following?
$\left(i\right)$ The set of right triangles.
$\left(ii\right)$ The set of isosceles triangles.

Answer 1

By definition, A universal set is a set which contains all the elements or objects of other sets in a particular context, including its own elements.

$\left(i\right)$ For the set of right triangles, the universal set can be the set of all triangles or set of polygons.

$\left(ii\right)$ For the set of isosceles triangles, the universal set can be the set of all triangles or set of polygons.