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Finding the Fourth Proportional to 739.78, 1,021.32 and 491.44

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Solution

The fourth proportional to 739.78, 1,021.32 and 491.44 is: 678.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    739.78 : 1,021.32 = 491.44 : x
  2. Step 2: Convert to fraction form
    739.78/1,021.32 = 491.44/x
  3. Step 3: Cross multiply
    739.78x = 1,021.32 × 491.44
  4. Step 4: Simplify right side
    739.78x = 501,917.50
  5. Step 5: Solve for x
    x = 501,917.50/739.78
  6. Step 6: Final answer
    x = 678.47

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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.