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Finding the Fourth Proportional to 620.64, 855.90 and 489.96

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Solution

The fourth proportional to 620.64, 855.90 and 489.96 is: 675.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.64 : 855.90 = 489.96 : x
  2. Step 2: Convert to fraction form
    620.64/855.90 = 489.96/x
  3. Step 3: Cross multiply
    620.64x = 855.90 × 489.96
  4. Step 4: Simplify right side
    620.64x = 419,356.76
  5. Step 5: Solve for x
    x = 419,356.76/620.64
  6. Step 6: Final answer
    x = 675.68

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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.