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Finding the Fourth Proportional to 745.31, 1,029.89 and 721.28

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Solution

The fourth proportional to 745.31, 1,029.89 and 721.28 is: 996.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    745.31 : 1,029.89 = 721.28 : x
  2. Step 2: Convert to fraction form
    745.31/1,029.89 = 721.28/x
  3. Step 3: Cross multiply
    745.31x = 1,029.89 × 721.28
  4. Step 4: Simplify right side
    745.31x = 742,835.45
  5. Step 5: Solve for x
    x = 742,835.45/745.31
  6. Step 6: Final answer
    x = 996.68

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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.