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Finding the Fourth Proportional to 20,978, 31,467 and 8,666.32

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Solution

The fourth proportional to 20,978, 31,467 and 8,666.32 is: 12,999.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,978 : 31,467 = 8,666.32 : x
  2. Step 2: Convert to fraction form
    20,978/31,467 = 8,666.32/x
  3. Step 3: Cross multiply
    20,978x = 31,467 × 8,666.32
  4. Step 4: Simplify right side
    20,978x = 272,703,091.44
  5. Step 5: Solve for x
    x = 272,703,091.44/20,978
  6. Step 6: Final answer
    x = 12,999.48

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Why These Related Problems?

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