Skip to main content
OlympiadHQ

Browse · harp

Print

jmc

geometry junior

Problem

A regular octahedron has eight equilateral triangle faces with four faces meeting at each vertex. Jun will make the regular octahedron shown on the right by folding the piece of paper shown on the left. Which numbered face will end up to the right of ?
(A)
(B)
(C)
(D)
Solution
We color face red and face yellow. Note that from the octahedron, face and face do not share anything in common. From the net, face shares at least one vertex with all other faces except face which is shown in green: Therefore, the answer is
Final answer
A