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Finding the Fourth Proportional to 457.31, 685.89 and 128.27

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Solution

The fourth proportional to 457.31, 685.89 and 128.27 is: 192.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    457.31 : 685.89 = 128.27 : x
  2. Step 2: Convert to fraction form
    457.31/685.89 = 128.27/x
  3. Step 3: Cross multiply
    457.31x = 685.89 × 128.27
  4. Step 4: Simplify right side
    457.31x = 87,979.11
  5. Step 5: Solve for x
    x = 87,979.11/457.31
  6. Step 6: Final answer
    x = 192.38

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.