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Finding the Fourth Proportional to 638.80, 958.20 and 557.80

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Solution

The fourth proportional to 638.80, 958.20 and 557.80 is: 836.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.80 : 958.20 = 557.80 : x
  2. Step 2: Convert to fraction form
    638.80/958.20 = 557.80/x
  3. Step 3: Cross multiply
    638.80x = 958.20 × 557.80
  4. Step 4: Simplify right side
    638.80x = 534,483.96
  5. Step 5: Solve for x
    x = 534,483.96/638.80
  6. Step 6: Final answer
    x = 836.70

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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.