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Finding the Fourth Proportional to 257.54, 386.35 and 86.50

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Solution

The fourth proportional to 257.54, 386.35 and 86.50 is: 129.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.54 : 386.35 = 86.50 : x
  2. Step 2: Convert to fraction form
    257.54/386.35 = 86.50/x
  3. Step 3: Cross multiply
    257.54x = 386.35 × 86.50
  4. Step 4: Simplify right side
    257.54x = 33,419.28
  5. Step 5: Solve for x
    x = 33,419.28/257.54
  6. Step 6: Final answer
    x = 129.76

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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.