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Finding the Fourth Proportional to 851.28, 1,278.54 and 486.78

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Solution

The fourth proportional to 851.28, 1,278.54 and 486.78 is: 731.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.28 : 1,278.54 = 486.78 : x
  2. Step 2: Convert to fraction form
    851.28/1,278.54 = 486.78/x
  3. Step 3: Cross multiply
    851.28x = 1,278.54 × 486.78
  4. Step 4: Simplify right side
    851.28x = 622,367.70
  5. Step 5: Solve for x
    x = 622,367.70/851.28
  6. Step 6: Final answer
    x = 731.10

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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.