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Finding the Fourth Proportional to 989.78, 1,365.09 and 616.05

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Solution

The fourth proportional to 989.78, 1,365.09 and 616.05 is: 849.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.78 : 1,365.09 = 616.05 : x
  2. Step 2: Convert to fraction form
    989.78/1,365.09 = 616.05/x
  3. Step 3: Cross multiply
    989.78x = 1,365.09 × 616.05
  4. Step 4: Simplify right side
    989.78x = 840,963.69
  5. Step 5: Solve for x
    x = 840,963.69/989.78
  6. Step 6: Final answer
    x = 849.65

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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.