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Finding the Fourth Proportional to 989.78, 1,365.80 and 547.61

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Solution

The fourth proportional to 989.78, 1,365.80 and 547.61 is: 755.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.78 : 1,365.80 = 547.61 : x
  2. Step 2: Convert to fraction form
    989.78/1,365.80 = 547.61/x
  3. Step 3: Cross multiply
    989.78x = 1,365.80 × 547.61
  4. Step 4: Simplify right side
    989.78x = 747,916.17
  5. Step 5: Solve for x
    x = 747,916.17/989.78
  6. Step 6: Final answer
    x = 755.64

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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.