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Finding the Fourth Proportional to 399.09, 551.49 and 385.41

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Solution

The fourth proportional to 399.09, 551.49 and 385.41 is: 532.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.09 : 551.49 = 385.41 : x
  2. Step 2: Convert to fraction form
    399.09/551.49 = 385.41/x
  3. Step 3: Cross multiply
    399.09x = 551.49 × 385.41
  4. Step 4: Simplify right side
    399.09x = 212,549.76
  5. Step 5: Solve for x
    x = 212,549.76/399.09
  6. Step 6: Final answer
    x = 532.59

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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.