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Finding the Fourth Proportional to 911.80, 1,367.76 and 391.88

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Solution

The fourth proportional to 911.80, 1,367.76 and 391.88 is: 587.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.80 : 1,367.76 = 391.88 : x
  2. Step 2: Convert to fraction form
    911.80/1,367.76 = 391.88/x
  3. Step 3: Cross multiply
    911.80x = 1,367.76 × 391.88
  4. Step 4: Simplify right side
    911.80x = 535,997.79
  5. Step 5: Solve for x
    x = 535,997.79/911.80
  6. Step 6: Final answer
    x = 587.85

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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.