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Finding the Fourth Proportional to 216.12, 324.17 and 86.19

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Solution

The fourth proportional to 216.12, 324.17 and 86.19 is: 129.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.12 : 324.17 = 86.19 : x
  2. Step 2: Convert to fraction form
    216.12/324.17 = 86.19/x
  3. Step 3: Cross multiply
    216.12x = 324.17 × 86.19
  4. Step 4: Simplify right side
    216.12x = 27,940.43
  5. Step 5: Solve for x
    x = 27,940.43/216.12
  6. Step 6: Final answer
    x = 129.28

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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.