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Finding the Fourth Proportional to 664.78, 917.56 and 381.28

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Solution

The fourth proportional to 664.78, 917.56 and 381.28 is: 526.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.78 : 917.56 = 381.28 : x
  2. Step 2: Convert to fraction form
    664.78/917.56 = 381.28/x
  3. Step 3: Cross multiply
    664.78x = 917.56 × 381.28
  4. Step 4: Simplify right side
    664.78x = 349,847.28
  5. Step 5: Solve for x
    x = 349,847.28/664.78
  6. Step 6: Final answer
    x = 526.26

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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.