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Finding the Fourth Proportional to 391.28, 586.85 and 147.80

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Solution

The fourth proportional to 391.28, 586.85 and 147.80 is: 221.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.28 : 586.85 = 147.80 : x
  2. Step 2: Convert to fraction form
    391.28/586.85 = 147.80/x
  3. Step 3: Cross multiply
    391.28x = 586.85 × 147.80
  4. Step 4: Simplify right side
    391.28x = 86,737.16
  5. Step 5: Solve for x
    x = 86,737.16/391.28
  6. Step 6: Final answer
    x = 221.68

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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.