MathDB
Square to Polyhedron

Source:

March 15, 2006
geometry3D geometrytetrahedron

Problem Statement

Three 12 cm ×\times 12 cm squares are each cut into two pieces AA and BB, as shown in the first figure below, by joining the midpoints of two adjacent sides. These six pieces are then attached to a regular hexagon, as shown in the second figure, so as to fold into a polyhedron. What is the volume (in cm3\text{cm}^3) of this polyhedron?
[asy] defaultpen(fontsize(10)); size(250); draw(shift(0, sqrt(3)+1)*scale(2)*rotate(45)*polygon(4)); draw(shift(-sqrt(3)*(sqrt(3)+1)/2, -(sqrt(3)+1)/2)*scale(2)*rotate(165)*polygon(4)); draw(shift(sqrt(3)*(sqrt(3)+1)/2, -(sqrt(3)+1)/2)*scale(2)*rotate(285)*polygon(4)); filldraw(scale(2)*polygon(6), white, black); pair X=(2,0)+sqrt(2)*dir(75), Y=(-2,0)+sqrt(2)*dir(105), Z=(2*dir(300))+sqrt(2)*dir(225); pair[] roots={2*dir(0), 2*dir(60), 2*dir(120), 2*dir(180), 2*dir(240), 2*dir(300)}; draw(roots[0]--X--roots[1]); label("BB", centroid(roots[0],X,roots[1])); draw(roots[2]--Y--roots[3]); label("BB", centroid(roots[2],Y,roots[3])); draw(roots[4]--Z--roots[5]); label("BB", centroid(roots[4],Z,roots[5])); label("AA", (1+sqrt(3))*dir(90)); label("AA", (1+sqrt(3))*dir(210)); label("AA", (1+sqrt(3))*dir(330)); draw(shift(-10,0)*scale(2)*polygon(4)); draw((sqrt(2)-10,0)--(-10,sqrt(2))); label("AA", (-10,0)); label("BB", centroid((sqrt(2)-10,0),(-10,sqrt(2)),(sqrt(2)-10, sqrt(2))));[/asy]