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Finding the Fourth Proportional to 457.61, 686.34 and 128.57

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Solution

The fourth proportional to 457.61, 686.34 and 128.57 is: 192.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    457.61 : 686.34 = 128.57 : x
  2. Step 2: Convert to fraction form
    457.61/686.34 = 128.57/x
  3. Step 3: Cross multiply
    457.61x = 686.34 × 128.57
  4. Step 4: Simplify right side
    457.61x = 88,241.55
  5. Step 5: Solve for x
    x = 88,241.55/457.61
  6. Step 6: Final answer
    x = 192.83

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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.