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Finding the Fourth Proportional to 911.28, 1,255.68 and 724.80

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Solution

The fourth proportional to 911.28, 1,255.68 and 724.80 is: 998.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.28 : 1,255.68 = 724.80 : x
  2. Step 2: Convert to fraction form
    911.28/1,255.68 = 724.80/x
  3. Step 3: Cross multiply
    911.28x = 1,255.68 × 724.80
  4. Step 4: Simplify right side
    911.28x = 910,116.86
  5. Step 5: Solve for x
    x = 910,116.86/911.28
  6. Step 6: Final answer
    x = 998.72

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.