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Finding the Fourth Proportional to 1,985.40, 2,978.43 and 686.52

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Solution

The fourth proportional to 1,985.40, 2,978.43 and 686.52 is: 1,029.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,985.40 : 2,978.43 = 686.52 : x
  2. Step 2: Convert to fraction form
    1,985.40/2,978.43 = 686.52/x
  3. Step 3: Cross multiply
    1,985.40x = 2,978.43 × 686.52
  4. Step 4: Simplify right side
    1,985.40x = 2,044,751.76
  5. Step 5: Solve for x
    x = 2,044,751.76/1,985.40
  6. Step 6: Final answer
    x = 1,029.89

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