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

Question

Philoid · Accepted Answer

(i) We know that right triangles are a type of triangle with an angle 90°

Thus, a set of triangles will contain all the right triangles.

∴universal set, U = {x: x is a triangle in plane}

(ii) We know that isosceles triangles are a type of triangle with any two of the angles equal in measure.

Thus, a set of triangles will contain all the isosceles triangles.

∴ universal set, U = {x: x is a triangle in plane}