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Finding the Fourth Proportional to 638.98, 881.80 and 386.87

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Solution

The fourth proportional to 638.98, 881.80 and 386.87 is: 533.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.98 : 881.80 = 386.87 : x
  2. Step 2: Convert to fraction form
    638.98/881.80 = 386.87/x
  3. Step 3: Cross multiply
    638.98x = 881.80 × 386.87
  4. Step 4: Simplify right side
    638.98x = 341,136.59
  5. Step 5: Solve for x
    x = 341,136.59/638.98
  6. Step 6: Final answer
    x = 533.88

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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.