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Finding the Fourth Proportional to 491.98, 682.61 and 487.78

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Solution

The fourth proportional to 491.98, 682.61 and 487.78 is: 676.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.98 : 682.61 = 487.78 : x
  2. Step 2: Convert to fraction form
    491.98/682.61 = 487.78/x
  3. Step 3: Cross multiply
    491.98x = 682.61 × 487.78
  4. Step 4: Simplify right side
    491.98x = 332,963.51
  5. Step 5: Solve for x
    x = 332,963.51/491.98
  6. Step 6: Final answer
    x = 676.78

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.