MathDB
Square Around Equilateral Triangles

Source:

February 19, 2008
geometrytrigonometry

Problem Statement

Points K K, L L, M M, and N N lie in the plane of the square ABCD ABCD so that AKB AKB, BLC BLC, CMD CMD, and DNA DNA are equilateral triangles. If ABCD ABCD has an area of 16 16, find the area of KLMN KLMN.
[asy]unitsize(2cm); defaultpen(fontsize(8)+linewidth(0.8)); pair A=(-0.5,0.5), B=(0.5,0.5), C=(0.5,-0.5), D=(-0.5,-0.5); pair K=(0,1.366), L=(1.366,0), M=(0,-1.366), N=(-1.366,0); draw(A--N--K--A--B--K--L--B--C--L--M--C--D--M--N--D--A); label("AA",A,SE); label("BB",B,SW); label("CC",C,NW); label("DD",D,NE); label("KK",K,NNW); label("LL",L,E); label("MM",M,S); label("NN",N,W);[/asy]
(A)\ 32 \qquad (B)\ 16 \plus{} 16\sqrt {3} \qquad (C)\ 48 \qquad (D)\ 32 \plus{} 16\sqrt {3} \qquad (E)\ 64