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Finding the Fourth Proportional to 392.87, 542.15 and 218.20

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Solution

The fourth proportional to 392.87, 542.15 and 218.20 is: 301.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.87 : 542.15 = 218.20 : x
  2. Step 2: Convert to fraction form
    392.87/542.15 = 218.20/x
  3. Step 3: Cross multiply
    392.87x = 542.15 × 218.20
  4. Step 4: Simplify right side
    392.87x = 118,297.13
  5. Step 5: Solve for x
    x = 118,297.13/392.87
  6. Step 6: Final answer
    x = 301.11

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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.