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Finding the Fourth Proportional to 851.78, 1,279.30 and 487.28

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Solution

The fourth proportional to 851.78, 1,279.30 and 487.28 is: 731.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.78 : 1,279.30 = 487.28 : x
  2. Step 2: Convert to fraction form
    851.78/1,279.30 = 487.28/x
  3. Step 3: Cross multiply
    851.78x = 1,279.30 × 487.28
  4. Step 4: Simplify right side
    851.78x = 623,377.30
  5. Step 5: Solve for x
    x = 623,377.30/851.78
  6. Step 6: Final answer
    x = 731.85

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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.