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Finding the Fourth Proportional to 1,287.73, 1,777.17 and 728.20

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Solution

The fourth proportional to 1,287.73, 1,777.17 and 728.20 is: 1,004.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.73 : 1,777.17 = 728.20 : x
  2. Step 2: Convert to fraction form
    1,287.73/1,777.17 = 728.20/x
  3. Step 3: Cross multiply
    1,287.73x = 1,777.17 × 728.20
  4. Step 4: Simplify right side
    1,287.73x = 1,294,135.19
  5. Step 5: Solve for x
    x = 1,294,135.19/1,287.73
  6. Step 6: Final answer
    x = 1,004.97

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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.