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Finding the Fourth Proportional to 257.56, 386.34 and 129.40

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Solution

The fourth proportional to 257.56, 386.34 and 129.40 is: 194.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.56 : 386.34 = 129.40 : x
  2. Step 2: Convert to fraction form
    257.56/386.34 = 129.40/x
  3. Step 3: Cross multiply
    257.56x = 386.34 × 129.40
  4. Step 4: Simplify right side
    257.56x = 49,992.40
  5. Step 5: Solve for x
    x = 49,992.40/257.56
  6. Step 6: Final answer
    x = 194.10

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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.