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Finding the Fourth Proportional to 639.40, 881.82 and 499.30

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Solution

The fourth proportional to 639.40, 881.82 and 499.30 is: 688.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.40 : 881.82 = 499.30 : x
  2. Step 2: Convert to fraction form
    639.40/881.82 = 499.30/x
  3. Step 3: Cross multiply
    639.40x = 881.82 × 499.30
  4. Step 4: Simplify right side
    639.40x = 440,292.73
  5. Step 5: Solve for x
    x = 440,292.73/639.40
  6. Step 6: Final answer
    x = 688.60

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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.