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Finding the Fourth Proportional to 391.89, 587.91 and 135.39

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Solution

The fourth proportional to 391.89, 587.91 and 135.39 is: 203.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.89 : 587.91 = 135.39 : x
  2. Step 2: Convert to fraction form
    391.89/587.91 = 135.39/x
  3. Step 3: Cross multiply
    391.89x = 587.91 × 135.39
  4. Step 4: Simplify right side
    391.89x = 79,597.13
  5. Step 5: Solve for x
    x = 79,597.13/391.89
  6. Step 6: Final answer
    x = 203.11

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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.