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Finding the Fourth Proportional to 989.82, 1,365.97 and 641.11

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Solution

The fourth proportional to 989.82, 1,365.97 and 641.11 is: 884.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.82 : 1,365.97 = 641.11 : x
  2. Step 2: Convert to fraction form
    989.82/1,365.97 = 641.11/x
  3. Step 3: Cross multiply
    989.82x = 1,365.97 × 641.11
  4. Step 4: Simplify right side
    989.82x = 875,737.03
  5. Step 5: Solve for x
    x = 875,737.03/989.82
  6. Step 6: Final answer
    x = 884.74

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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.