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Finding the Fourth Proportional to 911.31, 1,257.80 and 557.29

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Solution

The fourth proportional to 911.31, 1,257.80 and 557.29 is: 769.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.31 : 1,257.80 = 557.29 : x
  2. Step 2: Convert to fraction form
    911.31/1,257.80 = 557.29/x
  3. Step 3: Cross multiply
    911.31x = 1,257.80 × 557.29
  4. Step 4: Simplify right side
    911.31x = 700,959.36
  5. Step 5: Solve for x
    x = 700,959.36/911.31
  6. Step 6: Final answer
    x = 769.18

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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.