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Finding the Fourth Proportional to 392.88, 542.14 and 215.80

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Solution

The fourth proportional to 392.88, 542.14 and 215.80 is: 297.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.88 : 542.14 = 215.80 : x
  2. Step 2: Convert to fraction form
    392.88/542.14 = 215.80/x
  3. Step 3: Cross multiply
    392.88x = 542.14 × 215.80
  4. Step 4: Simplify right side
    392.88x = 116,993.81
  5. Step 5: Solve for x
    x = 116,993.81/392.88
  6. Step 6: Final answer
    x = 297.79

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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.