text: 1) three fourths of 900 = 675\n25% of 900 = 225\n% decrease = (675-225)/675 = 66.67% \n\n2) Total no. of cows = 25% or 1/4 of total no. of animals on farm\nTotal no. of bulls = 3/9 of total no. of animals on farm\nRatio of no. of cows to no. of bulls = 1/4 : 3/9 = 25:33\n\n3) Let radius be x.\nArea of circle = Pi multiplied by x squared.\nIf radius is increased by 25%, new radius = 1.25x\nNew area of circle = Pi multiplied by 1.25x squared.\n% increase = (Area of new circle divided by Area of circle) - 1\n=  56.25%