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Finding the Fourth Proportional to 997.31, 1,376.11 and 665.21

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Solution

The fourth proportional to 997.31, 1,376.11 and 665.21 is: 917.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    997.31 : 1,376.11 = 665.21 : x
  2. Step 2: Convert to fraction form
    997.31/1,376.11 = 665.21/x
  3. Step 3: Cross multiply
    997.31x = 1,376.11 × 665.21
  4. Step 4: Simplify right side
    997.31x = 915,402.13
  5. Step 5: Solve for x
    x = 915,402.13/997.31
  6. Step 6: Final answer
    x = 917.87

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.