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Finding the Fourth Proportional to 399.78, 551.61 and 225.09

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Solution

The fourth proportional to 399.78, 551.61 and 225.09 is: 310.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.78 : 551.61 = 225.09 : x
  2. Step 2: Convert to fraction form
    399.78/551.61 = 225.09/x
  3. Step 3: Cross multiply
    399.78x = 551.61 × 225.09
  4. Step 4: Simplify right side
    399.78x = 124,161.89
  5. Step 5: Solve for x
    x = 124,161.89/399.78
  6. Step 6: Final answer
    x = 310.58

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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.