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Finding the Fourth Proportional to 399.52, 551.78 and 355.78

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Solution

The fourth proportional to 399.52, 551.78 and 355.78 is: 491.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.52 : 551.78 = 355.78 : x
  2. Step 2: Convert to fraction form
    399.52/551.78 = 355.78/x
  3. Step 3: Cross multiply
    399.52x = 551.78 × 355.78
  4. Step 4: Simplify right side
    399.52x = 196,312.29
  5. Step 5: Solve for x
    x = 196,312.29/399.52
  6. Step 6: Final answer
    x = 491.37

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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.