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Finding the Fourth Proportional to 214.47, 321.89 and 86.31

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Solution

The fourth proportional to 214.47, 321.89 and 86.31 is: 129.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    214.47 : 321.89 = 86.31 : x
  2. Step 2: Convert to fraction form
    214.47/321.89 = 86.31/x
  3. Step 3: Cross multiply
    214.47x = 321.89 × 86.31
  4. Step 4: Simplify right side
    214.47x = 27,781.89
  5. Step 5: Solve for x
    x = 27,781.89/214.47
  6. Step 6: Final answer
    x = 129.54

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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.