A rectangle is 8 cm long. If its length is reduced by 3 cm, it becomes a square. How many square centimeters has its area been reduced?

The rectangle is 8 cm long, 8-3 = 5 cm wide and S = 8 * 5 = 40 square cm
Square area s = 5 * 5 = 25 square centimeter
Area reduction = 40-25 = 15 cm2

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