MathDB
Two Trapezoids

Source:

June 8, 2009
geometrytrapezoidratiosimilar triangles

Problem Statement

The parallel sides of a trapezoid are 3 3 and 9 9. The non-parallel sides are 4 4 and 6 6. A line parallel to the bases divides the trapezoid into two trapezoids of equal perimeters. The ratio in which each of the non-parallel sides is divided is: [asy]defaultpen(linewidth(.8pt)); unitsize(2cm);
pair A = origin; pair B = (2.25,0); pair C = (2,1); pair D = (1,1); pair E = waypoint(A--D,0.25); pair F = waypoint(B--C,0.25);
draw(A--B--C--D--cycle); draw(E--F);
label("6",midpoint(A--D),NW); label("3",midpoint(C--D),N); label("4",midpoint(C--B),NE); label("9",midpoint(A--B),S);[/asy]<spanclass=latexbold>(A)</span> 4:3<spanclass=latexbold>(B)</span> 3:2<spanclass=latexbold>(C)</span> 4:1<spanclass=latexbold>(D)</span> 3:1<spanclass=latexbold>(E)</span> 6:1 <span class='latex-bold'>(A)</span>\ 4: 3\qquad <span class='latex-bold'>(B)</span>\ 3: 2\qquad <span class='latex-bold'>(C)</span>\ 4: 1\qquad <span class='latex-bold'>(D)</span>\ 3: 1\qquad <span class='latex-bold'>(E)</span>\ 6: 1