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) Right triangle is a type of triangle. So the set of triangles contain all types of triangles.

$\therefore$ U = {x : x is a triangle in plane}

(ii) Isosceles triangle is a type of triangle. So the set of triangles contain all types of triangles.

$\therefore$ U = {x : x is a triangle in plane}