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Finding the Fourth Proportional to 664.60, 918.30 and 489.64

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Solution

The fourth proportional to 664.60, 918.30 and 489.64 is: 676.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.60 : 918.30 = 489.64 : x
  2. Step 2: Convert to fraction form
    664.60/918.30 = 489.64/x
  3. Step 3: Cross multiply
    664.60x = 918.30 × 489.64
  4. Step 4: Simplify right side
    664.60x = 449,636.41
  5. Step 5: Solve for x
    x = 449,636.41/664.60
  6. Step 6: Final answer
    x = 676.55

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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.