What is a possible way to tile the plane with a pentagon with three 90° angles and two equal obtuse angles?
I: three at a vertex
II: three or four at a vertex
A) I only
B) II only
C) both I and II
D) neither I nor II

Question

What is a possible way to tile the plane with a pentagon with three 90° angles and two equal obtuse angles? 
I: three at a vertex
II: three or four at a vertex
A) I only
B) II only
C) both I and II
D) neither I nor II

Quizplus · Accepted Answer

A pentagon with three 90° angles and two equal obtuse angles is called a trirectangular pentagon. It is not possible to tile the plane with this type of pentagon using only three at a vertex. However, it is possible to tile the plane using four at a vertex, which means choice II is possible. Therefore, the answer is B – II only.

What Is a Possible Way to Tile the Plane with a Pentagon