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Finding the Fourth Proportional to 665.78, 918.72 and 385.97

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Solution

The fourth proportional to 665.78, 918.72 and 385.97 is: 532.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.78 : 918.72 = 385.97 : x
  2. Step 2: Convert to fraction form
    665.78/918.72 = 385.97/x
  3. Step 3: Cross multiply
    665.78x = 918.72 × 385.97
  4. Step 4: Simplify right side
    665.78x = 354,593.76
  5. Step 5: Solve for x
    x = 354,593.76/665.78
  6. Step 6: Final answer
    x = 532.60

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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.