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Finding the Fourth Proportional to 620.45, 855.12 and 489.23

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Solution

The fourth proportional to 620.45, 855.12 and 489.23 is: 674.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.45 : 855.12 = 489.23 : x
  2. Step 2: Convert to fraction form
    620.45/855.12 = 489.23/x
  3. Step 3: Cross multiply
    620.45x = 855.12 × 489.23
  4. Step 4: Simplify right side
    620.45x = 418,350.36
  5. Step 5: Solve for x
    x = 418,350.36/620.45
  6. Step 6: Final answer
    x = 674.27

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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.