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Finding the Fourth Proportional to 676.77, 1,015.79 and 639.78

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Solution

The fourth proportional to 676.77, 1,015.79 and 639.78 is: 960.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    676.77 : 1,015.79 = 639.78 : x
  2. Step 2: Convert to fraction form
    676.77/1,015.79 = 639.78/x
  3. Step 3: Cross multiply
    676.77x = 1,015.79 × 639.78
  4. Step 4: Simplify right side
    676.77x = 649,882.13
  5. Step 5: Solve for x
    x = 649,882.13/676.77
  6. Step 6: Final answer
    x = 960.27

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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.