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Finding the Fourth Proportional to 989.78, 1,365.92 and 547.68

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Solution

The fourth proportional to 989.78, 1,365.92 and 547.68 is: 755.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.78 : 1,365.92 = 547.68 : x
  2. Step 2: Convert to fraction form
    989.78/1,365.92 = 547.68/x
  3. Step 3: Cross multiply
    989.78x = 1,365.92 × 547.68
  4. Step 4: Simplify right side
    989.78x = 748,087.07
  5. Step 5: Solve for x
    x = 748,087.07/989.78
  6. Step 6: Final answer
    x = 755.81

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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.