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Finding the Fourth Proportional to 392.58, 542.07 and 318.78

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Solution

The fourth proportional to 392.58, 542.07 and 318.78 is: 440.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.58 : 542.07 = 318.78 : x
  2. Step 2: Convert to fraction form
    392.58/542.07 = 318.78/x
  3. Step 3: Cross multiply
    392.58x = 542.07 × 318.78
  4. Step 4: Simplify right side
    392.58x = 172,801.07
  5. Step 5: Solve for x
    x = 172,801.07/392.58
  6. Step 6: Final answer
    x = 440.17

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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.