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Finding the Fourth Proportional to 215.38, 322.92 and 85.30

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Solution

The fourth proportional to 215.38, 322.92 and 85.30 is: 127.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.38 : 322.92 = 85.30 : x
  2. Step 2: Convert to fraction form
    215.38/322.92 = 85.30/x
  3. Step 3: Cross multiply
    215.38x = 322.92 × 85.30
  4. Step 4: Simplify right side
    215.38x = 27,545.08
  5. Step 5: Solve for x
    x = 27,545.08/215.38
  6. Step 6: Final answer
    x = 127.89

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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.