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Angle Bisectors and Proportionality

Line AD bisects angle A (ie. cuts the angle in half). Drag points B and C to manipulate the diagram. The spreadsheet at the right shows the lengths of the sides AB, AC, BD, and CD as well as the ratios. AB/AC shows the ratio of the side lengths on either side of the bisected angle, A. BD/CD shows the ratio of the two segments created by the angle bisector on the 3rd side. Are the ratios AB/AC and BD/CD always equal?