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Finding the Fourth Proportional to 820.78, 1,132.70 and 489.26

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Solution

The fourth proportional to 820.78, 1,132.70 and 489.26 is: 675.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.78 : 1,132.70 = 489.26 : x
  2. Step 2: Convert to fraction form
    820.78/1,132.70 = 489.26/x
  3. Step 3: Cross multiply
    820.78x = 1,132.70 × 489.26
  4. Step 4: Simplify right side
    820.78x = 554,185.19
  5. Step 5: Solve for x
    x = 554,185.19/820.78
  6. Step 6: Final answer
    x = 675.20

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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.