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kropki game

Find the image of the square ABCD under the homothety with center O and ratio k=1/2. Draw rays from point O through points A, B, C, D. Find with compass point A' that line segment OA' is two times smaller as OA. In the same way find point B', C', D'. Join points A', B', C' and D'. We get the image of the square ABCD under the homothety with center $O$ and ratio k = 1/2.