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Finding the Fourth Proportional to 391.75, 587.64 and 103.20

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Solution

The fourth proportional to 391.75, 587.64 and 103.20 is: 154.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.75 : 587.64 = 103.20 : x
  2. Step 2: Convert to fraction form
    391.75/587.64 = 103.20/x
  3. Step 3: Cross multiply
    391.75x = 587.64 × 103.20
  4. Step 4: Simplify right side
    391.75x = 60,644.45
  5. Step 5: Solve for x
    x = 60,644.45/391.75
  6. Step 6: Final answer
    x = 154.80

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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.