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Finding the Fourth Proportional to 739.78, 1,021.32 and 641.38

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Solution

The fourth proportional to 739.78, 1,021.32 and 641.38 is: 885.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    739.78 : 1,021.32 = 641.38 : x
  2. Step 2: Convert to fraction form
    739.78/1,021.32 = 641.38/x
  3. Step 3: Cross multiply
    739.78x = 1,021.32 × 641.38
  4. Step 4: Simplify right side
    739.78x = 655,054.22
  5. Step 5: Solve for x
    x = 655,054.22/739.78
  6. Step 6: Final answer
    x = 885.47

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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.