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Finding the Fourth Proportional to 721.96, 993.78 and 638.94

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Solution

The fourth proportional to 721.96, 993.78 and 638.94 is: 879.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.96 : 993.78 = 638.94 : x
  2. Step 2: Convert to fraction form
    721.96/993.78 = 638.94/x
  3. Step 3: Cross multiply
    721.96x = 993.78 × 638.94
  4. Step 4: Simplify right side
    721.96x = 634,965.79
  5. Step 5: Solve for x
    x = 634,965.79/721.96
  6. Step 6: Final answer
    x = 879.50

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.