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Finding the Fourth Proportional to 393.12, 542.28 and 255.12

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Solution

The fourth proportional to 393.12, 542.28 and 255.12 is: 351.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.12 : 542.28 = 255.12 : x
  2. Step 2: Convert to fraction form
    393.12/542.28 = 255.12/x
  3. Step 3: Cross multiply
    393.12x = 542.28 × 255.12
  4. Step 4: Simplify right side
    393.12x = 138,346.47
  5. Step 5: Solve for x
    x = 138,346.47/393.12
  6. Step 6: Final answer
    x = 351.92

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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.