156.--THE DISSECTED TRIANGLE.

A good puzzle is that which the gentleman in the illustration is showing

to his friends. He has simply cut out of paper an equilateral

triangle--that is, a triangle with all its three sides of the same

length. He proposes that it shall be cut into five pieces in such a way

that they will fit together and form either two or three smaller

equilateral triangles, using all the material in each case. Can you

discover how the cuts should be made?

Remember that when you have made your five pieces, you must be able, as

desired, to put them together to form either the single original

triangle or to form two triangles or to form three triangles--all

equilateral.

Amusements in Mathematics · 第 184 / 970 题