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Finding the Fourth Proportional to 639.98, 961.34 and 458.54

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Solution

The fourth proportional to 639.98, 961.34 and 458.54 is: 688.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.98 : 961.34 = 458.54 : x
  2. Step 2: Convert to fraction form
    639.98/961.34 = 458.54/x
  3. Step 3: Cross multiply
    639.98x = 961.34 × 458.54
  4. Step 4: Simplify right side
    639.98x = 440,812.84
  5. Step 5: Solve for x
    x = 440,812.84/639.98
  6. Step 6: Final answer
    x = 688.79

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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.