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Finding the Fourth Proportional to 639.90, 884.79 and 557.89

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Solution

The fourth proportional to 639.90, 884.79 and 557.89 is: 771.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.90 : 884.79 = 557.89 : x
  2. Step 2: Convert to fraction form
    639.90/884.79 = 557.89/x
  3. Step 3: Cross multiply
    639.90x = 884.79 × 557.89
  4. Step 4: Simplify right side
    639.90x = 493,613.28
  5. Step 5: Solve for x
    x = 493,613.28/639.90
  6. Step 6: Final answer
    x = 771.39

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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.