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Finding the Fourth Proportional to 639.12, 882.42 and 489.48

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Solution

The fourth proportional to 639.12, 882.42 and 489.48 is: 675.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.12 : 882.42 = 489.48 : x
  2. Step 2: Convert to fraction form
    639.12/882.42 = 489.48/x
  3. Step 3: Cross multiply
    639.12x = 882.42 × 489.48
  4. Step 4: Simplify right side
    639.12x = 431,924.74
  5. Step 5: Solve for x
    x = 431,924.74/639.12
  6. Step 6: Final answer
    x = 675.81

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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.