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Finding the Fourth Proportional to 731.28, 1,009.26 and 420.78

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Solution

The fourth proportional to 731.28, 1,009.26 and 420.78 is: 580.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    731.28 : 1,009.26 = 420.78 : x
  2. Step 2: Convert to fraction form
    731.28/1,009.26 = 420.78/x
  3. Step 3: Cross multiply
    731.28x = 1,009.26 × 420.78
  4. Step 4: Simplify right side
    731.28x = 424,676.42
  5. Step 5: Solve for x
    x = 424,676.42/731.28
  6. Step 6: Final answer
    x = 580.73

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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.