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Finding the Fourth Proportional to 621.87, 858.50 and 489.18

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Solution

The fourth proportional to 621.87, 858.50 and 489.18 is: 675.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.87 : 858.50 = 489.18 : x
  2. Step 2: Convert to fraction form
    621.87/858.50 = 489.18/x
  3. Step 3: Cross multiply
    621.87x = 858.50 × 489.18
  4. Step 4: Simplify right side
    621.87x = 419,961.03
  5. Step 5: Solve for x
    x = 419,961.03/621.87
  6. Step 6: Final answer
    x = 675.32

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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.