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Finding the Fourth Proportional to 989.78, 1,365.89 and 547.66

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Solution

The fourth proportional to 989.78, 1,365.89 and 547.66 is: 755.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.78 : 1,365.89 = 547.66 : x
  2. Step 2: Convert to fraction form
    989.78/1,365.89 = 547.66/x
  3. Step 3: Cross multiply
    989.78x = 1,365.89 × 547.66
  4. Step 4: Simplify right side
    989.78x = 748,034.60
  5. Step 5: Solve for x
    x = 748,034.60/989.78
  6. Step 6: Final answer
    x = 755.76

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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.