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Finding the Fourth Proportional to 372.31, 558.33 and 128.78

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Solution

The fourth proportional to 372.31, 558.33 and 128.78 is: 193.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    372.31 : 558.33 = 128.78 : x
  2. Step 2: Convert to fraction form
    372.31/558.33 = 128.78/x
  3. Step 3: Cross multiply
    372.31x = 558.33 × 128.78
  4. Step 4: Simplify right side
    372.31x = 71,901.74
  5. Step 5: Solve for x
    x = 71,901.74/372.31
  6. Step 6: Final answer
    x = 193.13

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.