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Finding the Fourth Proportional to 391.78, 587.38 and 148.20

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Solution

The fourth proportional to 391.78, 587.38 and 148.20 is: 222.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.78 : 587.38 = 148.20 : x
  2. Step 2: Convert to fraction form
    391.78/587.38 = 148.20/x
  3. Step 3: Cross multiply
    391.78x = 587.38 × 148.20
  4. Step 4: Simplify right side
    391.78x = 87,049.72
  5. Step 5: Solve for x
    x = 87,049.72/391.78
  6. Step 6: Final answer
    x = 222.19

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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.