Question

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

Answer 1

(i) For the set of right triangles, the universal set can be the set of triangles or the set of polygons.
(ii) For the set of isosceles triangles, the universal set can be the set of triangles or the set of polygons or the set of two-dimensional figures.