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Finding the Fourth Proportional to 216.31, 324.14 and 86.17

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Solution

The fourth proportional to 216.31, 324.14 and 86.17 is: 129.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.31 : 324.14 = 86.17 : x
  2. Step 2: Convert to fraction form
    216.31/324.14 = 86.17/x
  3. Step 3: Cross multiply
    216.31x = 324.14 × 86.17
  4. Step 4: Simplify right side
    216.31x = 27,929.90
  5. Step 5: Solve for x
    x = 27,929.90/216.31
  6. Step 6: Final answer
    x = 129.12

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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.