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Finding the Fourth Proportional to 391.40, 587.18 and 147.92

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Solution

The fourth proportional to 391.40, 587.18 and 147.92 is: 221.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.40 : 587.18 = 147.92 : x
  2. Step 2: Convert to fraction form
    391.40/587.18 = 147.92/x
  3. Step 3: Cross multiply
    391.40x = 587.18 × 147.92
  4. Step 4: Simplify right side
    391.40x = 86,851.99
  5. Step 5: Solve for x
    x = 86,851.99/391.40
  6. Step 6: Final answer
    x = 221.90

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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.