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Finding the Fourth Proportional to 391.75, 587.64 and 103.21

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Solution

The fourth proportional to 391.75, 587.64 and 103.21 is: 154.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.75 : 587.64 = 103.21 : x
  2. Step 2: Convert to fraction form
    391.75/587.64 = 103.21/x
  3. Step 3: Cross multiply
    391.75x = 587.64 × 103.21
  4. Step 4: Simplify right side
    391.75x = 60,650.32
  5. Step 5: Solve for x
    x = 60,650.32/391.75
  6. Step 6: Final answer
    x = 154.82

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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.