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Finding the Fourth Proportional to 820.53, 1,131.90 and 489.09

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Solution

The fourth proportional to 820.53, 1,131.90 and 489.09 is: 674.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.53 : 1,131.90 = 489.09 : x
  2. Step 2: Convert to fraction form
    820.53/1,131.90 = 489.09/x
  3. Step 3: Cross multiply
    820.53x = 1,131.90 × 489.09
  4. Step 4: Simplify right side
    820.53x = 553,600.97
  5. Step 5: Solve for x
    x = 553,600.97/820.53
  6. Step 6: Final answer
    x = 674.69

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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.