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Finding the Fourth Proportional to 257.56, 386.28 and 86.56

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Solution

The fourth proportional to 257.56, 386.28 and 86.56 is: 129.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.56 : 386.28 = 86.56 : x
  2. Step 2: Convert to fraction form
    257.56/386.28 = 86.56/x
  3. Step 3: Cross multiply
    257.56x = 386.28 × 86.56
  4. Step 4: Simplify right side
    257.56x = 33,436.40
  5. Step 5: Solve for x
    x = 33,436.40/257.56
  6. Step 6: Final answer
    x = 129.82

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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.