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Finding the Fourth Proportional to 1,287.47, 1,776.41 and 868.60

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Solution

The fourth proportional to 1,287.47, 1,776.41 and 868.60 is: 1,198.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.47 : 1,776.41 = 868.60 : x
  2. Step 2: Convert to fraction form
    1,287.47/1,776.41 = 868.60/x
  3. Step 3: Cross multiply
    1,287.47x = 1,776.41 × 868.60
  4. Step 4: Simplify right side
    1,287.47x = 1,542,995.75
  5. Step 5: Solve for x
    x = 1,542,995.75/1,287.47
  6. Step 6: Final answer
    x = 1,198.47

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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.