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Finding the Fourth Proportional to 639.28, 881.49 and 499.42

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Solution

The fourth proportional to 639.28, 881.49 and 499.42 is: 688.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.28 : 881.49 = 499.42 : x
  2. Step 2: Convert to fraction form
    639.28/881.49 = 499.42/x
  3. Step 3: Cross multiply
    639.28x = 881.49 × 499.42
  4. Step 4: Simplify right side
    639.28x = 440,233.74
  5. Step 5: Solve for x
    x = 440,233.74/639.28
  6. Step 6: Final answer
    x = 688.64

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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.