Three circles with radii 3, 6, and 9 ft are externally tangent to one another, as shown in the figure. Find the area of the sector of the circle of radius 3 that is cut off by the line segments joining the center of that circle to the centers of the other two circles.
ft?

Given: ae ≅ ce ; de ≅ be prove: abcd is a parallelogram. we have that ab || dc. by a similar argument used to prove that △aeb ≅ △ced, we can show that △ ≅ △ceb by. so, ∠cad ≅ ∠ by cpctc. therefore, ad || bc by the converse of the theorem. since both pair of opposite sides are parallel, quadrilateral abcd is a parallelogram.