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Finding the Fourth Proportional to 399.72, 551.20 and 281.48

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Solution

The fourth proportional to 399.72, 551.20 and 281.48 is: 388.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.72 : 551.20 = 281.48 : x
  2. Step 2: Convert to fraction form
    399.72/551.20 = 281.48/x
  3. Step 3: Cross multiply
    399.72x = 551.20 × 281.48
  4. Step 4: Simplify right side
    399.72x = 155,151.78
  5. Step 5: Solve for x
    x = 155,151.78/399.72
  6. Step 6: Final answer
    x = 388.15

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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.